GSC Power-Division Exhaust 23-8N Chrome Polished Valve Set of 8, 29mm STD (gsc2021-8) 2551 external air flows into the

external air flows into the grill and through the stock openings over the engine for an extra cooling effect

HP4-XTSS kit features an Xtreme pressure plate for the most demanding driver

Multi-ply silicone design with internal wire reinforcement

High quality materials to last the lifetime of your 997

Invidia offers several exhaust system product lines to meet the expectations of nearly any automotive enthusiast

GSC Power-Division Exhaust 23-8N Chrome Polished Valve Set of 8, 29mm STD (gsc2021-8) 2551 external air flows into theWhen creating our new valve line we set out to create the best performance, longest lasting valves available to the aftermarket. Using advanced 3D design and simulation software, we have created a stronger and higher flowing valve head design. We flow test prototype valve heads in the specific applications to make sure we have the highest flowing valve head available on the market today. With the materials used, we have less valve distortion at the