Congratulations — you've decided to transform your BMW F87 M2 with the MHC+ GTX Aero Package. Now comes the part that matters: getting it on the car properly. Below is the complete fitting guide for the GTX front splitter, side skirts and rear diffuser, so you achieve the fitment the kit was designed around.
The GTX package is a full pre-preg carbon fibre aero system for the F87 M2, developed as one cohesive design rather than a collection of separate parts. Everything in this guide applies to both the Non-Competition (N55) and Competition (S55) M2 — the only component that differs between the two cars is the front splitter, which is model-specific. Side skirts and rear diffuser are shared across both.
| Fitment | BMW F87 M2 & M2 Competition |
| Difficulty | Moderate — drilling required |
| Time (full kit) | Allow a full day, unrushed |
| Best done | Indoors, above 15°C, on a clean dry car |
Read this first. Every GTX component is bonded and mechanically fixed. Once the double-sided tape is fully committed and the pilot holes are drilled, there is no repositioning. Trial fit everything, twice, before you peel a single length of backing tape. Take your time at the alignment stage and the rest of the job looks after itself.
TOOLS & MATERIALS
All the fixings you need are supplied in the box, along with the drill bits, driver bit and alcohol wipes for surface prep. Here is the full tool list for the job — anything marked (supplied) is already in your kit:
- A trusty drill
- 2.5mm drill bit (supplied) — pilot holes for all self-tapping screws
- 6.5mm drill bit (supplied) — front splitter adjustable lower only
- PZ2 driver bit (supplied)
- 10mm socket and 10mm spanner — you'll need both for the diffuser M6 hardware
- 8mm socket — rear bumper corner OEM fixings
- Panel wipe or IPA (isopropyl alcohol) and lint-free cloths
- Masking tape
- Trim removal tools
- Ramps, or a jack and axle stands
- (Optional, but genuinely worth it) a mate to hold the other end
Supplied in the box
Pre-applied automotive double-sided tape · alcohol wipes · 4.8 x 13mm self-tapping screws · M6 nuts and bolts · threaded uppers · fitting billets · 2.5mm drill bit · 6.5mm drill bit · PZ2 driver bit. Your OEM fixings are reused throughout — keep every one you remove.
GTX FRONT SPLITTER
The GTX front splitter is the aerodynamic anchor of the package. It's available as an upper section on its own, or as an upper plus adjustable lower — and which one you've bought changes how much of this section applies to you.
Bumper on or bumper off? The splitter upper can be fitted with the front bumper still on the car — Stages 1 to 3 only. If you're fitting the adjustable lower, the bumper has to come off, so it's worth removing it from the outset and doing the whole job on the bench.
Fixing point reference
Every fixing location on the splitter is colour-coded on the diagram below. Keep this to hand — it tells you which holes get drilled, which get billets, and which reuse OEM hardware.
GTX front splitter fixing point locations, viewed from the underside of the bumper.
Stage 1 — Preparation
- Remove all OEM fittings from the underside of the bumper — these are the points shown in red on the diagram. Keep them somewhere safe; they all go back in.
- Wipe the bumper underside down thoroughly with IPA or panel wipe to remove all residue, dust, road film and oils. The tape is only as good as the surface underneath it.
- Peel back roughly two inches of the pre-applied tape backing at each end of the splitter, and use masking tape to hold the backing out of the way ready to be pulled off fully later.
Stage 2 — Trial fitment
- Offer the splitter upper up so it sits flush with both arches and is centred on the bumper.
- Loosely fit the OEM screws to hold it in position.
- Stand back and check the alignment properly — both ends, both arches, and the gap along the full length. Adjust until you're genuinely happy.
- Once satisfied, tighten the OEM screws fully.
- Peel the remaining tape backing off completely and press the splitter firmly along its whole length.
Stage 3 — Drilling and fastening the upper
- Using a 2.5mm drill bit, pilot drill every green location shown on the diagram.
- Fit the supplied 4.8 x 13mm self-tapping screws into all drilled holes with a PZ2 bit. Nip them up snug — carbon doesn't appreciate being over-torqued.
Fitting the upper only? That's you finished on the front. Skip to the side skirts.
Stage 4 — Adjustable lower: mounting preparation
- Remove the front bumper from the car with the upper splitter attached.
- Drill through the lower mounting holes using a 6.5mm bit — the blue locations on the diagram.
- Place the fitting billets inside the splitter upper.
Stage 5 — Adjustable lower: assembly
- Position the splitter lower and check the amount of forward protrusion. This is the point where “adjustable” earns its name — set it where you want it before you commit.
- Fit the M6 bolts through the splitter lower and through the billets.
- Align the threaded uppers inside the bumper, making sure they sit flush. Peel back part of the pre-applied double-sided tape and start to bond them in place.
- Peel the rest of the tape backing off the threaded uppers and loosely thread both M6 bolts into them.
- Tighten the M6 bolts, making sure the threaded uppers sit flush and are fully bonded.
Stage 6 — Final refit
- Refit the bumper to the car with the splitter attached, and reinstate all OEM fixings.
GTX SIDE SKIRTS
The easiest component in the package by a distance, and the one that does the most to visually lower the car. No bumper removal, no bench work — straight onto the sill. The same skirts fit both the M2 and the M2 Competition.
- A trusty drill with a 2.5mm bit (supplied)
- PZ2 driver bit (supplied)
- Panel wipe or IPA and lint-free cloths
- Supplied alcohol wipes and self-tapping screws
Fitting
- Wipe the sill down thoroughly to remove dirt and road film.
- Go over the sill again with the supplied alcohol wipes and let it flash off.
- Peel roughly two inches of tape backing off each end of the skirt — just enough to let you position it without committing.
- Align the skirt flush with the arches at both ends.
- Align the back edge of the skirt with the underside of the sill rail.
- Check it over. Walk to the other end of the car and check it again. Once you're happy with the alignment, remove all the remaining tape backing and press the skirt home along its full length.
- Pilot drill each fixing hole with a 2.5mm bit.
- Screw in the supplied self-tappers with a PZ2 bit.
- Repeat on the other side.
Get both ends right at once. Flush to the arches and aligned to the sill rail — those two references together are what make the skirt look factory. Chasing one at the expense of the other is the most common way to end up with a skirt that reads slightly off.
GTX REAR DIFFUSER
The GTX rear diffuser is available as an upper section on its own — a straight swap for the OEM item — or as the full two-piece system with the lower undertray and corners. Both fit the M2 and M2 Competition.
- A trusty drill with a 2.5mm bit (supplied)
- PZ2 driver bit (supplied)
- 10mm socket and 10mm spanner (M6 nuts and bolts — you need to hold both ends)
- 8mm socket (corner OEM fixings)
- Panel wipe or IPA and lint-free cloths
- Supplied alcohol wipes, M6 hardware and self-tappers
Option A — Upper section only
- Remove the old diffuser.
- Clip the new GTX diffuser into place — give it a firm push all the way along to make sure every clip is properly engaged.
- Screw the OEM self-tappers back in on the underside.
That's the upper done. If you're not fitting the lower undertray, you're finished.
Option B — Upper, lower undertray and corners
Assemble on the bench first. Build the diffuser up as a complete unit before it goes anywhere near the car.
- Using the supplied M6 nuts and bolts, bolt the diffuser together with a 10mm socket and spanner. There are 6 bolts joining the upper and lower sections.
- Fit the remaining 4 bolts holding the corners to the diffuser lower — 2 on each side.
Now prep the car.
- Remove the 2 x 8mm OEM fixings from the underside of each corner.
- Wipe the corner areas down to remove dirt and road film.
- Go over them again with the supplied alcohol wipes.
- Peel two inches of tape off either side. This is enough to help you hold alignment without fixing the piece permanently in place.
And fit.
- Clip the diffuser upper into place, then align the OEM fixings with the fixing points on the diffuser corners.
- Align the faces of the diffuser corners with the arch — this is the alignment that matters most visually, so take your time over it.
- Replace the OEM fixings and tighten them loosely.
- Remove the rest of the tape backing.
- Tighten the OEM fixings fully.
- Pilot drill the remaining fixing holes with a 2.5mm bit.
- Fit the supplied self-tappers into the drilled holes.
Done.
FINAL CHECKS & AFTERCARE
- Walk the car and check every panel gap and arch alignment from a few metres back, in daylight.
- Confirm every self-tapper is seated and every OEM fixing has gone back where it came from.
- Leave the car to stand before washing or pressure washing — give the bonded surfaces time to settle undisturbed.
- Keep the pressure washer lance away from the bonded edges and tape lines when you do wash it.
- Give the fixings a quick once-over after your first few hundred miles.
GALLERY
Need a hand?
If anything doesn't look right during the fit, stop and talk to us before you drill. We'd far rather answer a question than see a part fitted twice.
Contact MHC