Valvetronic Design Porsche 991.2 Carrera Valved Sport Exhaust SystemWhen the 991. 1 generation 911 was replaced by the . 2, the addition of 2 noise killing turbo chargers frightened us dearly. As with many vehicles, when you add turbos it kills a lot of the emotion and drama. At Valvetronic Designs we know that sound is the staple for emotion. With our 991. 2 exhaust package we give your 911 the soul back it deserves. We solve the sound issue starting at the exhaust manifolds, running our CAD designed and CFD tested