15-16 BMW S1000XR: Akrapovic Slip-On Exhaust (EURO3/Black Titanium) Akrapovic exhausts are the most sought after exhaust systems for their unmatched quality, amazing sound, beautiful style, and unrivaled performance. The Akrapovic Slip-On line represents the first step in exhaust system tuning. It is simple to install and replaces a stock muffler. Change the nature of your bike by adding more power, improved performance, and the unique Akrapovic sound. Everything packed in stylishly designed Slip-On exhaust systems.