Porsche 991 Carrera /S/GTS Valved exhaust system 2012-2016Welcome to the Valvetronic Designs Catback system for the 991 Platform. This system has been designed from the ground up to give very rich F1 sound and to provide minimal frequencies when running in the valves closed mode. Featuring a large center X pipe, this valved system is the ideal setup for the 991 platform Porsche 911. Features of this Valved Exhaust Constructed from T304 Stainless Steel or blue burnt titanium Vacuum exhaust valves with