For ultimate tuning potential, additional weight reduction, and a great racing sound, we offer stainless steel down pipes without cats. These high-flow down pipes require ECU reprogramming and are a perfect fit with the Evolution performance exhaust system. 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.