Valvetronic Design Porsche GT3 991.1 / 991.2 Valved Sport Exhaust SystemThe FULL RSR experience. This system is truly unparalleled in sound quality. In the quest for the most incredible, highest pitched, and most enjoyable sound characteristic possible, our last year and a half of research and development has led us to a sound experience that must be heard in person to be believed. For the 991 generation of the GT3 The DFI engine was chosen in favor of the Mezger and many people were afraid that it would lose its classic