The Billy Boat Performance Exhaust PRT C7 exhaust system is the latest in resonance control technology from B&B. Completey redesigned and reengineered for the C7, the system is simple indesign, though more complex in theory. This Billy Boat Performance Exhaust PRT system works purely on physics and adrenaline. The Billy Boat C7 PRT exhaust incorporates our own version of the factory-designed butterfly valve to control backpressure and sound when your C7 goes into economy mode, maintaining all the technology from the factory. Unlike the factory base model C7, which only has a 2.0' outlet for the exhaust, the Billy Boat PRT allows a mellow sound at cruising speeds and a sport note when you're tearing up the streets. It allows true straight through exhaust passage under agressive driving conditions, though a mellow sound is emitted at cruising speeds thanks to the unique Purge Chamber.