Do you want the benefit of having the full noise and power of an open header at full throttle but also keeping it quiet for cruising the streets? Thanks to Aeroflow Performance the boost activated exhaust control valve (ECV) you can have the best of both worlds. No more wiring up expensive and unreliable electric exhaust cut-outs and no more climbing underneath the car to open the manual exhaust cut-outs. It's just a matter of hooking up the boost referenced vacuum line or a mac valve solenoid and you are ready to go. These ECV is for use with turbocharged vehicles and will open the exhaust valve when boost reaches roughly 6-7 psi. Allowing a quieter exhaust when driving around normally. The higher pressures can be obtained with either a installing a manual boost controller or a mac valve solenoid. The exhaust valve is normally closed for all applications. Installation requires fabrication work to weld into the current exhaust system with a T-piece or Y-piece (Sold Separately).