Agency Power has developed one of the best sounding and performing exhaust systems for the 2011 STi Sedan. The new exhaust features an all T304 stainless steel piping in 3inch diameter from the catback. The piping is all hand polished featuring robotic TIG welding. The midpipe includes a resonator to assist in keeping that traditional boxxer engine sound with an exotic race tone touch that does not drone in the cabin. The ½ inch thick flanges offer a secure fit along with the factory placement exhaust hangers. The catback exhaust uses a high flow Y-Pipe to efficiently direct exhaust to the dual exhaust canisters. The Y-pipe features a merged collector and 3 inch piping on each extension to give your exhaust a combined 5 inches of exhaust flow. The straight through mufflers are designed to optimize horsepower with very little restriction. The catback exhaust features quad 3.5 inch tips with the Agency Power logo. As tested on a Mustang all wheel drive dyno, the Agency Power catback exhaust made an impressive 17 all wheel horsepower and 28ft/lbs of torque. The exhausts are available for 2011+ STi WRX Sedans.