Slip-on system (S-PO/TI/15) for GT3 RS / Speedster OPF model must be mandatory combined with:- Evolution Header Set (E-PO/T/6)- Tail pipe set TP-T/S/19. When combining the slip-on system with optional carbon fibre diffuser DI-PO/CA/7/G (fits on GT3 RS), you must use tail pipe set TP-T/S/17.- An additional original Porsche stock bracket (Porsche p/n: 99111147391) is required for mounting the Akrapovič exhaust system. Please read the instructions carefully before the start of the installation.This Slip-On system (S-PO/TI/15) must be upgraded into a full Akrapovič Evolution Line exhaust system by combining it with the Evolution Header Set (E-PO/T/6) with side mufflers and valves, which is designed to unleash the system’s full potential and enhance the performance of the car as the revs rise. With superb attention to detail, including parts cast in Akrapovič’s own titanium foundry, the craftsmanship and coating finish on the system is a joy to behold. With an exhaust manifold incorporating 100 cpsi sports catalytic convertors and side mufflers, the Evolution Line utilizes integrated catalytic convertors and the functionality of the exhaust valves to deliver an out-and-out attack on the senses. It offers increased weight savings in the area behind the engine and rear axle. The Evolution Line is also tuned to deliver a sporty and hard-hitting sound. The more the engine is revved and the acceleration builds, the six-cylinder engine sound delivers a rich, harmonic, and high-frequency soundtrack, making every journey a memorable experience and one that continues even after the throttle is released, providing a full and rewarding sensory experience. When installing Akrapovič aftermarket optional link 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 Akrapovič 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.