The equal length design of the PERRIN header, produces smoother more balanced exhaust pulses flow from the head to the turbocharger giving you the best of two worlds. Quicker turbo response as well as more horsepower and torque throughout the entire RPM band. While designed to fit to the factory up-pipe, our header will mate with an OEM or aftermarket up-pipe, as well as any rotated turbo kits compatible with the factory header.
You wont see grossly over sized tubing to make Perrin header LOOK better as this just slows exhaust gases down and looses response. This header uses 1.5" primary tubing that is expanded at the flange to fit the Subaru exhaust port size. This size of tubing is perfectly designed for cars up to 400WHP. You can see from Perrin's dyno graphs that even on cars with well over 400 wheel horsepower there is a significant gain in HP and TQ across the entire RPM band over a stock header. For those looking to go way beyond 500 wheel horsepower, check out Perrin's Big Tube Equal Length Header.