The Akrapovič Evolution and Slip-On line exhaust systems can be further enhanced with an optional hand-crafted carbon-fiber rear diffuser. Developed by Akrapovič’s Design Department, this stunning diffuser, crafted from materials developed through Akrapovič’s racing involvement, is designed to perfectly fit the lines of the unique tailpipes of the Slip-On or Evolution systems, as well as complement the sleek and sporty shape of the BMW. When mounting Akrapovic rear carbon fiber diffuser BMW comfort access system will not work.