BMW M3 and M4 are the same car from the firewall forward — but they wear different body panels, which means different carbon fiber fitment lists. If you own both or are planning builds on each, here is exactly what differs and what crosses over.
What the G80 M3 and G82 M4 Share
Mechanically, the G80 M3 and G82 M4 use the same S58 engine, same suspension geometry, same subframes, and the same front bumper assembly. Front bumper carbon fiber parts — splitters, canards, front lip extensions — are identical between G80 and G82. Same fitment, same mounting points, same aero effect. You can buy one front aero setup and it works on either car.
What Is Different Between G80 and G82
Hood
The G80 sedan and G82 coupe use different hoods. The coupe's hood is shaped to the lower roofline and different A-pillar angle — it does not transfer to the sedan. Always specify G80 or G82 when ordering a carbon fiber hood.
Trunk Lid
Different body entirely. The G80 sedan trunk and G82 coupe trunk are unique to each body style. Carbon fiber trunk lids and ducktail spoilers must be model-specific.
Rear Diffuser
The rear bumper lower fascias differ between sedan and coupe. While the aesthetic similarity is high, the precise geometry of the diffuser attachment points and bumper cut lines are body-specific. G80 diffusers do not fit G82 and vice versa — confirm body style when ordering.
Roof
Different roof dimensions due to different body structure. Carbon fiber roof skins and roof spoilers are model-specific. The G82 M4 also has an available M Carbon Exterior Package from BMW that includes an OEM carbon roof — aftermarket carbon roofs must be designed around this consideration.
Carbon Fiber That Universally Fits Both
Mirror caps, front splitters, front canards, and front bumper carbon accents are shared fitment. These are the safest cross-model purchases and excellent starting points for either build.
Building Both Cars: Where to Start
If you are building an M3 and an M4, start with the shared parts — one front aero kit covers both. Then add model-specific hoods, trunks, and diffusers for each. This approach minimizes SKUs and maximizes visual consistency across both cars if you want them to match.