Constructed from?high-quality stainless steel?, this optional addition to the Slip-On Line will enhance the sound of the exhaust, and power will be taken to greater heights. Fitted with sporty catalytic converters, installing this option increases the engine?s?performance?and adds an aural improvement for all to appreciate. Providing?improved flow?for the exhaust gases, the link pipes take the 911 to greater heights.When installing Akrapovic aftermarket optional down pipes with sports catalytic converters or without catalytic converters, which are developed for use on closed tracks only, remapping the ECU is mandatory. When installing Akrapovic aftermarket exhaust system that was developed for use on closed tracks, we recommend remapping the ECU in order to prevent potential ?check engine light? warning signals.THIS PRODUCT DOES NOT MEET EMISSION COMPLIANCE REQUIREMENTS FOR STREET OR HIGHWAY USE.