The Milltek Sport Large-Bore Downpipe with Hi-Flow Sports Cat delivers improved performance and a deeper exhaust tone. Its larger diameter reduces back pressure, allowing exhaust gases to flow more freely and boosting engine efficiency. When combined with the Hi-Flow Sports Cat, it provides maximum power gains and a sportier driving experience. Built for enthusiasts who want to unlock their car’s full potential with reliable, long-lasting performance. Specifications - Pipe diameter (inches): 3.7 - Feature 1: 3.7'' ID Turbo Outlet to 3.15'' Downpipe with 200CPSI HJS Cat (No CEL) - Feature 2: Fits with Milltek Cat Back System Only