Optional available headers from the finest titanium offer an upgrade to a full system when used with the Akrapovič Slip-On exhaust system. Let your bike stand out with more power, beautiful design, and the unique Akrapovič sound. Featuring exhaust valve for improved rideability in lower rpm. Optional headers fit also with Akrapovič standard (first fit) / BMW accessory Akrapovič silencer. When installing optional headers E-B12E4, remapping the ECU is recommended in order to prevent »check engine light« warning signal and achieve optimized performance and throttle response. THIS PRODUCT DOES NOT MEET EMISSION COMPLIANCE REQUIREMENTS FOR STREET OR HIGHWAY USE.