TurboXS Catback Exhaust - Fits 04-08 Forester XTThe Forester XT Exhaust uses our 3 inch from the front flange all the way to our Staight through design muffler with a 3. 5 inch tip. This is hands the the best sounding exhaust for the Forester XT and to top it all off it doesn't reduce down to 2. 5 inches anywhere unlike some of the other exhaust systems. You should see a 10 12 whp gain with this catback without a problem.