Invidia's one-piece, equal length 05-09 Legacy GT header includes an integrated dual tube uppipe for optimal flow, performance and ease of installation. This header and uppipe combo will provide your engine flow with much more efficient internal path providing power and torque gains throughout the rev range. While pricey, rest assured that Invidia's header is constructed of stainless steel with top-quality welds and is designed to make the best gains available from an aftermarket header. Though engine tuning is recommended to realize full potential with any aftermarket exhaust header, Invidia has tested this unit to pull a solid +7.6 whp and +14.6 ft/lbs with absolutely no tuning! Fully tuned and optimized, you can expect 15-25hp on your Legacy GT.