Borla 09-12 Chevy Corvette C6 Coupe/Convertible 6.2L 8cyl Aggressive ATAK ExhaustThis system will fit vehicles with and without NPP valves. BORLA system does NOT include NPP valves. The single 2. 5" diameter Into the muffler with dual 2" out Cat Back delivers the Aggressive ATAK sound. ATAK Acoustically Tuned Applied Kinetics, technology is based on specifically tuned attributes of the internal muffler cores, which are calibrated on a vehicle by vehicle basis to deliver the most desirable sound. Even though the sound on the