BMW G80 M3 Modified as a Surprise: TREVORA PR-1, FORM Carbon and Eibach Pro-Kit

Last updated: 8 October 2026

Our friend Ross finally bought his dream car: a BMW G80 M3. Completely stock, xDrive, the lot. He has backed AUTOID since the very beginning, and we have known him for more than ten years, so we asked if we could borrow the car for a bit of product development and some 3D scanning.

That was a lie. By the time he got it back, it had over £7,000 of modifications on it, software included, and he had no idea any of it was happening.

This is the full story of how that G80 M3 was modified, part by part: what went on, why, how it was fitted, and what you need to know if you want to do the same to your own G80. We have kept it honest. Where the film tells us exactly what was fitted, we say so. Where it doesn't, we tell you how to choose rather than guess.

• Car: BMW M3 Saloon (G80), xDrive, completely standard on arrival
• Brief: OEM+, not a show car. Better stance, a protected engine, a sharper drive and a full carbon kit
• Parts: 13 catalogue parts, plus software and a couple of interior extras
• Time: a hard couple of days in the workshop
• Budget framing: over £7,000, as the film puts it, including the tune

The build at a glance

Shop the parts from this build

• Eibach Pro-Kit lowering springs
• Bimecc 5x112 hub-centric wheel spacer kit
• TREVORA front non-rub arch clearance kit
• TREVORA oil cooler skid guard
• FORM pre-preg carbon GT front kidney grilles (ACC and non-ACC versions)
• FORM pre-preg carbon performance front ducts
• TREVORA PR-1 pre-preg carbon front splitter
• TREVORA PR-1 pre-preg carbon side skirts
• TREVORA PR-1 pre-preg carbon rear spoiler
• FORM pre-preg carbon OEM-style rear diffuser
• FORM pre-preg carbon diffuser outline trim
• TREVORA pre-preg carbon wing mirror covers
• Plateless magnetic number plate kit, front and rear

What a stock G80 M3 gets wrong

Nobody buys a G80 M3 because they think it is slow. The S58 straight-six, the gearbox and the xDrive system are not the problem. The problem is how the car sits and how it looks when you walk up to it.

Nathan, one of the two technicians on the car, put it bluntly at the start of the film: the G series platform leaves the factory with "an almighty arch gap" at the front. The wheels sit tucked inside the arches too. And there is a quirk specific to the G80: the rear actually sits closer to where you want it than the front does, so the front needs more of a drop than the rear.

Then there is the face. The grilles are a massively common complaint on G80 forums. Our team's view, said on camera, is that you get used to them, but a carbon grille makes the front look a lot better. The honeycomb inserts in the side ducts don't match anything else on the car either.

Underneath, BMW put the oil cooler low behind the front bumper on most G series M cars. It is great for airflow and less great on British roads.

The brief: OEM+, not a show car

We could have gone further. We didn't, on purpose. Ross uses this as a real car, so the brief was a build that looks like BMW should have made it, not something that scrapes on every speed bump.

That shaped every choice. Eibach's Pro-Kit rather than an aggressive drop. Spacers sized to fill the arches rather than poke out of them. A splitter that adds presence without becoming a nuisance. As the team said at the reveal, everything was "quite like OEM plus", nothing "too ridiculously aggressive", but it "changes the car completely".

If you want a wider view of where to start on these cars, our first five mods for the G80 M3 and G82 M4 covers the logic. This post is what that logic looks like when you do the whole lot in one go.

Stance, part one: Eibach Pro-Kit springs

The springs were the Eibach Pro-Kit for the G80 and G81 M3. The joke in the workshop was that Ross is "a little bit of an old man" and wouldn't thank us for slamming it. The real reason is that the Pro-Kit is designed to work with the factory dampers and keep everyday comfort while taking out the arch gap.

The Pro-Kit comes in two versions for this car, and choosing the right one matters.

On this car we fitted option 2: approx. 20 mm at the front and approx. 10 mm at the rear. That matches the G80 quirk above. Drop the front more than the rear and the car finally sits level, the way it arguably should have left the factory. Eibach list the kit for the M3 Saloon, M3 Competition, M3 Competition xDrive and the M3 Touring.

Fitting the rear springs

Nathan did the rears, and they are the easier end. The basic job is to lower the arm, swap the spring and bolt it back up, but there are two things to get right:

• Mark the camber bolt before you undo it. A straight line across the bolt and the arm lets you put the camber back where it was. It is not a substitute for an alignment, but it keeps the car close to its factory setting until you get one.
• Unclip the headlight level sensor on the passenger side. If you don't, it will snap as the arm comes down.

Two bolts, the arm drops, out comes the old spring, in goes the Eibach, arm back up, torque it and you are done.

Fitting the front springs on an xDrive

Casper handled the fronts, which are harder because of the front driveshaft on xDrive cars. The correct method is to remove the strut from the car, swap the spring on the bench and refit the strut.

If you have suspension experience, you can do it the way you would on a rear-drive car: leave the strut in the hub, keep the driveshaft connected, and push the strut out to the side. That means removing the sensor, the anti-roll bar drop link, unclipping the brake line, disconnecting everything on the hub, supporting the hub and then undoing the top mount. It is quicker, but it is not a first suspension job.

Whichever end you do, the advice from the workshop is the same: always get a full alignment after fitting lowering springs.

Stance, part two: Bimecc wheel spacers

Lowering fixes the gap above the tyre. It does nothing for how far the wheel sits inside the arch. On a G80 that is a lot.

The Bimecc 5x112 spacer kit for the G80, G81, G82 and G83 went on as the last job before the wheels went back on: 15 mm at the front, with the rears spaced to suit, using Bimecc's extended bolts and the locking wheel bolt option.

The locking bolts matter. Fit spacers with extended plain bolts and you have quietly removed your locking wheel nuts. Bimecc's kit lets you choose extended locking bolts and a key, so the wheels stay protected. Bimecc spacers are also TÜV approved, which is the reassurance you want on something that sits between your hub and your wheel.

Front sizes on the listing run 10, 12, 15 and 20 mm, and the rear can be the same sizes or none at all. With locking bolts you get 16 extended black bolts, four locking bolts and a key. Without them you get 20 extended bolts. The spacers are hub-centric, with a 66.6 mm centre bore.

A word of warning, which the listing makes too: lowered and spaced, a G80 can rub, particularly at the front on some tyre choices. Our G82 shop car runs 15 mm front and rear without scrub on Michelin Pilot Sport 4S tyres, but other tyres have been reported to rub. That is why the next part on this car was not optional.

Fitting tip: put a thin smear of copper grease around the hub face before the spacer goes on. Surface rust can make spacers awkward to remove later. Nathan admitted on camera that his first smear was "a little bit excessive". You only need a small amount.

Clearing the rub: TREVORA front arch clearance kit

Lower a G80 and turn the wheel to full lock, and the tyre can catch the vent in front of the oil cooler. You hear it every time you park.

The fix is the TREVORA front non-rub arch clearance kit. The factory vent section is cut out and replaced with a TREVORA plate that sits further back from the tyre, still with a protective mesh. With the arch liners out, the kit goes in, and the liners go back. At the reveal it was one of the first things we pointed out to the owner: with the kit in, the front tyres no longer rub.

Two honest notes. Some product photos still show the older "TRE" logo; new kits come with the TREVORA logo, which is what you can see on this car. And because the factory vent is cut, this is the one part of the build you should treat as permanent. If you are on a lease, factor that in.

Protecting the S58: TREVORA oil cooler skid guard

This is the part most people don't think about until it is too late. On the G80, G82 and G87, the oil cooler sits low behind the front bumper. On smooth roads that is fine. On ours, it can be dented, chipped or cracked. Crack it and you can lose your engine oil and end up at the side of the road, with an S58 you really don't want to run dry.

The TREVORA oil cooler skid guard replaces the factory plastic guard with a 5052 aluminium plate that is stamped, CNC machined and powder-coated. If you hit something, the guard takes it, not the cooler. It bolts up from underneath with basic hand tools (an 8 mm socket and a T25 Torx driver, depending on the car) once the car is safely supported.

On camera, our team called it one of the most popular parts we sell for almost every new M car. That makes sense. It is cheap insurance against an expensive, car-stopping failure, and it fits the G80, G81, G82, G83 and G87.

The front end: FORM carbon GT grilles and performance ducts

With the bumper off (after a very awkward phone call asking Ross if we could take it off because we'd been "3D scanning" the car, having already removed it), the front end changed character completely.

FORM GT front kidney grilles

The grilles are FORM's pre-preg carbon GT front kidney grilles. Pre-preg (dry) carbon in a 2x2 weave, designed from 3D data, and light enough that it got handed round the workshop for a feel. They fit the same way the factory grilles do.

They replace the factory slats, which our team described on camera as looking "a bit like braces". The effect is more than cosmetic. With the slats gone and the carbon frame in place, the nose looks lower and more purposeful.

Choose the right version. The grilles come in two versions: with Active Cruise Control and without. Pick the one that matches your car's spec. If you aren't sure whether your car has ACC, check your build sheet or ask us before ordering.

FORM performance front ducts

The FORM pre-preg carbon performance front ducts replace the honeycomb duct inserts in the bumper corners. As we said in the film, there is no honeycomb anywhere else on the car, so it never made sense there. Carbon ducts tie in with the grilles and the splitter beneath them, and they keep the OEM mounting points.

Both parts install the same way as the factory ones once the bumper is off. That is the best moment to fit them, along with the next part.

Losing the plates: Plateless magnetic kit, front and rear

A carbon grille with a big UK plate across it is half the job. The Plateless magnetic number plate kit lets you pull the plate off for photos and shows, and put it back on for the road in seconds.

At the front, adhesive pads go on the back of the plate and magnets go behind the grille. One important point for G80, G81, G82 and G83 owners: Plateless list the standard M3 and M4 grilles as not compatible with the front kit. With an aftermarket grille, such as the FORM GT grilles here, it works. That is exactly why we recommend fitting the two together.

At the rear, it is even simpler if your boot lid is steel. The pads go on the plate and the plate sticks straight to the boot. You don't need backing magnets. On this car the rear plate went straight on and stayed put. As we said on camera, the plates are solid and "that will not move anywhere".

Fitting tip from the film: line the magnets up before you peel any 3M backing, so you can move them around. This car still had a long factory plate, so we set the magnets slightly inboard. If Ross ever fits a shorter plate, it won't overhang when he takes it on and off.

The TREVORA PR-1 kit: splitter, side skirts and spoiler

The centrepiece of the build. In the film we called the TREVORA PR-1 front splitter the best splitter you can get for the G series platform. We might be biased. But there are good reasons it went on Ross's car.

For the full kit breakdown, see our PR-1 carbon aero kit for the G80 M3 and G82 M4.

PR-1 front splitter

The PR-1 splitter is a three-piece design in pre-preg carbon with a 2x2 weave: a centre section and two side sections. It looks aggressive without sitting so low that it scrapes everywhere. Three pieces also means that if you damage one section, you replace that section, not the whole splitter.

Fitting it is straightforward:

1. Remove the two gloss black corner pieces from the factory bumper. The carbon side sections replace them.
2. Undo the six 10 mm bolts that hold the centre area.
3. Offer up the centre section and refit the bolts loosely to hold it.
4. Fit the side sections, line everything up and tighten.

It uses the factory mounting points with no extra bolts or drilling, and TREVORA's hidden bolt system keeps the fixings out of sight. It fits the G80 and G81 M3 and the G82 and G83 M4, pre-LCI and LCI.

PR-1 side skirts

The TREVORA PR-1 side skirts are a clean, flat skirt that carries the splitter's line down the length of the car. On a long saloon like the G80, that dark line along the bottom does a lot to make the car look lower.

We dropped the car onto blocks so the ramp arms were out of the way, and fitted one side each. Installation hardware is in the box and no modification is needed. Note the fitment: these are listed for the G80 and G81 M3 only, not the M4.

PR-1 rear spoiler

The TREVORA PR-1 rear spoiler is a properly long lip spoiler, taking cues from BMW's CS and Performance styling. It is listed for the G80 M3 and the G20 3 Series, so G82 owners need a different part.

How we fitted it:

1. Warm the factory spoiler with a heat gun and cut through the adhesive with fishing wire.
2. Remove all the old 3M tape, polish the area and clean it with a 3M prep wipe.
3. Peel back only the ends of the new spoiler's pre-applied 3M tape.
4. Sit the spoiler in place. With the backing still mostly on, you can slide it until it is perfectly aligned.
5. Pull the backing out, then press firmly and evenly along the whole length.

The kit includes adhesive promoter. TREVORA quote about 30 minutes to fit and an hour for the adhesive to set.

The back end: FORM rear diffuser and outline trim

At the back, the FORM pre-preg carbon OEM-style rear diffuser went on with the matching FORM diffuser outline trim. The diffuser follows the factory shape but in full carbon, and the trim replaces the surround around it. Together they finish the rear in the same material as the rest of the kit.

The factory diffuser comes off with four pop clips and then unclips. Be firm, because the clips are tight. Fit the outline trim first, pushing it into its clips, then the diffuser, which pushes into the original push clips, then refit the four pop clips. Both parts keep every OEM mounting point.

Our view from the film: once fitted, "it's going to be a very tasteful, expensive looking car". The photos agree.

Mirror caps without the broken glass

The TREVORA pre-preg carbon wing mirror covers replace the factory black covers outright. They aren't stick-on overlays. Every locating tab and mounting point matches the original, so they feel like OEM parts.

BMW's official method is to tilt the mirror glass, remove it, and unclip the cover. The risk is cracking the glass, which is expensive to replace on cars with lane assist, auto-dimming and heated mirrors. With experience there are safer ways to do it. On this car the clips survived and the glass did too. You also need to transfer the indicators to the new covers. If you aren't confident, have it fitted.

They come in right-hand and left-hand drive versions, so pick the one for your car. Fitment is broad: the G80, G81, G82, G83 and G87, plus the M240i (G42) and M340i LCI.

Inside, and under the bonnet

Two small interior changes made a surprisingly big difference. We fitted a set of magnetic paddle shifters in a satin carbon finish, real carbon fibre rather than the plastic of the originals, with a satisfying click on every change. We also fitted a satin screen protector to the iDrive display, which stops the glossy screen collecting fingerprints and protects it too. Our team said on camera that those two changes alone transformed how the interior felt. Browse the interior options in the G80 M3 parts collection.

Software by DefinedCoding

The software was carried out by DefinedCoding, who connected to the car using BMW's own OEM software. Ross got the full CS suite: engine, transmission, suspension, traction control and differential software from the M3 CS, plus CS steering and remote start. We are not the people to make power claims about someone else's work, so we'll leave that to them. If you want the same, talk to DefinedCoding directly.

What we can tell you is what he said on his first drive: the steering "feels a lot lighter", and the whole car felt more responsive.

The reveal

Towards the end of the build, Ross had been told we'd found a problem behind the bumper and needed to show him before it went back on. It was a reasonable story. It also wasn't true.

He pulled up, the shutter went up, and the car was waiting. We took him round it: carbon grilles, ducts, splitter, skirts, mirror caps, spoiler, diffuser and surround. Lowering springs, spacers, the arch clearance kit with no rub. The CS software. The paddles and the screen. The kerbed wheel had gone off for a refurb and came back in time too, on the condition he doesn't kerb it again.

His first reaction was "Well, I didn't expect that." His verdict after the drive: "Over the moon."

What he didn't know is that we'd been planning it since before he even bought the car.

What we didn't do, on purpose

It's worth being clear about what isn't on this car, because it shapes the result.

• No new wheels. Ross's own wheels stayed on. The kerbed one was refurbished, and the spacers did the work of filling the arches.
• No exhaust or intake. The sound changes come from the software alone. The team said on camera that the CS software adds a few more burbles and a deeper tone, but there's no hardware change here.
• No coilovers or aggressive drop. The Pro-Kit was a deliberate choice for a car that gets used every day. If you want to go lower, that's a different spring or a height-adjustable setup, and a different conversation about clearance.
• No paint or wrap. The factory colour stayed. The carbon does all the visual work.
• No widebody. Everything bolts to factory points.

That restraint is the point. Every part on the list either fixes something the factory got wrong or adds carbon in a way that looks like it belongs. There's nothing here the owner will want to undo in a year.

The full G80 M3 build list

Everything else for the car is in our BMW G80 M3 parts and accessories collection.

Will these parts fit my G81, G82, G83 or G87?

The G80 shares a lot with its siblings, but not everything. Here is what each listing says.

"No" here means "not this listing", not "nothing available". M4 and M2 owners have their own spring, skirt and spoiler options. G82 owners should look at our Ireland-to-Essex G82 M4 build, and G87 owners at the G87 M2 modding guide.

DIY or workshop?

Most of this build is within reach of a capable home mechanic with a lift or good axle stands. Some of it isn't. Here is how we'd judge each job based on what it took on this car.

How reversible is this build?

A lot of G80s are on finance or lease, so this matters. Most of this build can come off again. One part can't, and one needs care.

Keep every original part you take off, in a box, labelled. For more on this, read can I modify a lease car?

Why pre-preg carbon, and why it matters on a G80

Every carbon part on this car is pre-preg, sometimes called dry carbon. TREVORA and FORM both make the point on their listings that this is the same manufacturing method used for OEM carbon parts. For you, that means three things.

First, fit. FORM say pre-preg construction is what ensures fitment and durability, and that's borne out here: almost everything on this car went on with original clips, bolts and mounting points.

Second, finish. Every part here uses a 2x2 weave. If your G80 already has factory carbon, such as a carbon roof, carbon mirror trim or M Performance parts, the aftermarket parts sit beside it without looking like a different material.

Third, weight. The grilles are noticeably light, which was the first thing the team pointed out on camera, and TREVORA describe the PR-1 parts as light but strong.

There is one thing to bear in mind. Carbon is a finish as well as a material, so look after it like paint. Wash it with the rest of the car and protect it. If you want something you can scuff without worrying, the gloss black route below is the alternative.

PR-1 carbon or Zaero gloss black?

The other big G80 styling route we sell is Zaero's gloss black kits, which we have covered on a San Marino Blue G80 with the Zaero EVO-S kit and in our G80 M3 gloss black versus carbon comparison. This car shows the carbon route done properly.

Neither is wrong. What doesn't work is mixing a single carbon part into a gloss black car, or the other way round, without a plan. Pick one material and carry it all the way round, as this car does.

Before you order: the choices that catch people out

Most of the parts on this car come in more than one version, or only fit some of the G80's siblings. Getting these right first saves a return.

If you're unsure on any of these, send us your car's details before you order and we'll check.

How we'd stage this build on your G80

You don't have to do it all in one go. If you're building over time, this is the order we'd follow, and it's the same logic behind this car.

Living with it

A build like this should make the car better to own, not more stressful. Here's what to expect day to day.

• Ride. The Pro-Kit is designed to work with the factory dampers and keep the car comfortable for everyday driving. It's a modest drop, so speed bumps and driveways stay normal. It isn't a track setup.
• Splitter clearance. The PR-1 splitter was chosen because it doesn't sit so low that it scrapes everywhere. Steep ramps still deserve an angle.
• Spacers. Re-check wheel bolt torque after the first few miles, as you would after any wheel work, and keep the locking key somewhere sensible.
• Plates. The magnetic plates come off for photos and shows. They go back on for the road. That's the law, not a suggestion.
• Carbon care. Treat the carbon like paint: wash it properly and protect it from stone chips where you can.
• Insurance. Tell your insurer about the modifications. It is much easier to do it now than after a claim.
• Originals. Keep the factory grilles, ducts, diffuser, trim, mirror covers, corner pieces and springs. They matter if you sell the car or hand it back.

The parts that change daily life most are the ones you can't see. You won't hear the tyres catch at full lock, and the oil cooler is protected every time you drive over something you didn't see coming.

What it cost

The film calls it an over-£7,000 build, and that's the honest way to describe it: over £7,000 of modifications, the tune included. Live prices change, so we haven't listed them here. Each link above goes to the current catalogue page, and choices like spring option, spacer sizes and mirror version all affect the total.

If you want to stage it, the table above is the sensible way to spread it out. If you want it all done in one go, as it was here, talk to our team about fitting.

Watch the build

The full film covers every install in this post in real time, along with the phone calls, the fake problem and the reveal.

The AUTOID take

A stock G80 M3 is a brilliant car that looks unfinished. It sits too high at the front, the wheels hide in the arches, and the face divides opinion. None of that needs a widebody or a show-car drop to fix.

This build shows the order that works. Protect the oil cooler. Lower it the right amount at each end, using the Pro-Kit option that suits the G80. Fill the arches with sensible spacers and clear the rub properly. Then choose one material, carry it from the grille to the diffuser, and lose the plates for photos.

Ross drove away in a car that looks like the one BMW should have built. He also learned never to believe us when we say we need to borrow something for scanning.