Chevrolet Corvette (C6) Z06/ZR1 - Valved ExhaustOn the 2008 C6 with the NPP option, this valve is controlled by the onboard ECU. The valve opens based on RPM and throttle position. If you do not have a 2008 C6 with NPP, you need to order our CES 3 Kit separately. The iconic CAPRISTO Valved Exhaust System offers the best of both worlds through its capability to produce an aggressive exhaust note under acceleration, and a more subdued sound for city driving. At lower engine speeds and during cruise