UNIT 17 Carbon Fiber Side Skirt Extensions for BMW G80 M3 / G82 G83 M4UNIT 17 Carbon Fiber Side Skirt Extensions BMW G80 M3 G82 G83 M4 Extend the Rocker. No OEM Removal. These are undermount side skirt extensions not M Performance style replacements. Designed to mount beneath and extend beyond your existing OEM side skirts, they add a subtle low profile winglet that visually widens the stance of the car without replacing or modifying your factory rocker panels. The result is a sharper, lower, and more aggressive side