Side
80 products
Carbon fiber side aero parts along the length of the car: side skirts, mirror caps and vent trims for BMW, Audi and Mercedes-AMG. Most of the range is for the G80 M3, G82/G83 M4, G87 M2 and X3M/X4M.
Unit 17 designs its own side skirts for the G8X cars, the G87 M2, the X3M/X4M and the Audi RS3, and they are sold only here. Mirror caps and vent trims are mostly pre-preg dry carbon; some older skirt listings only say carbon fiber, and one F80 set is forged carbon.
Side buying guide
Side skirts, mirror caps or vent trims?
Side skirts change the car's stance the most. Extensions mount under the factory sills, while full replacements swap the gloss-black trim on the M3 and M4 skirts for carbon. Mirror caps are a small, visible change you see from the driver's seat: replacement caps take the place of the painted factory cap, and covers bond over it. Vent trims cover the fender vents and breathers, and this category also holds front bumper air ducts and inlets for the G8X, G87 and X3M/X4M LCI.
Building a matching side profile
If you want the side of the car to read as one piece, pick parts from the same family. On the G80 and G82, the MP-style full replacement skirts, the LHD mirror covers and the fender breathers are all pre-preg and follow M Performance shapes. On the G87 M2, the stepped detail on our side skirts matches our own front splitter. For the RS3 facelift, the S1 Pro lip and E1 Pro skirts are sold as a package.
Fitment details that catch people out
- The G8X and G87 replacement mirror covers are left-hand drive only, and one of the two M5 G90/G99 mirror listings is right-hand drive only.
- The F30/F80 M Performance-style skirt extensions fit the 3 and 4 Series M Sport and the M3, not the M4.
- Our X3M/X4M extensions stop just short of the factory underglow light so it still works.
- Some G20/G22 mirror covers don't fit the M340i and M440i facelift models.
What installation looks like
Side parts range from simple stick-on trims to jobs for a body shop. Vent trims often stick on with 3M tape, and the G8X fender breathers clip in once you move the fixings and badge across from the factory trim. Changing G20 mirror caps means taking out the mirror glass first. Many older skirt extensions come pre-drilled with self-tapping screws and need drilling into the factory skirt. Test-fit before you paint or drill anything.
Frequently asked questions
Why are front air ducts listed under Side?
The Vent Trims category groups every vent and duct trim together, so it holds fender vents and front bumper air ducts and inlets for the G8X, G87 M2, X3M/X4M LCI and other cars. The G8X lower air duct also appears under Bumper Trims & Accessories.
Do I need left-hand drive mirror caps for a US car?
Yes, US cars are left-hand drive. The G80/G82/G83 and G87 replacement mirror covers are made for left-hand drive only, because the driver's mirror on those cars is smaller. The G20/G22 caps let you pick LHD or RHD, and one M5 G90/G99 listing is right-hand drive only, so it won't suit a US M5.
Can carbon side skirts match my front splitter?
On some cars they are designed to. Our G87 M2 side skirts have a stepped detail that matches our G87 front splitter, and the RS3 facelift S1 Pro lip and E1 Pro skirts come as one package. On the G80 and G82, pair the MP-style skirts with other M Performance-style parts for a consistent look.
Do X3M side parts also fit the X4M?
Mostly. Our side skirt extensions, the fender vents and front side vents, and the OEM-style mirror caps are listed for both the X3M and X4M. The SQ-style side skirts for the LCI are listed for the X3M only, and LCI and pre-LCI front air ducts differ. The X3M/X4M LCI page shows only parts for the facelift.