Exhaust Swap: 02 Outback Sport Exhaust (Cat, and O2 sensors and all) onto 05 WRX

You do know that a naturally aspirated engine has a different exhaust system than a turbo car?

My buddy's correct. The "Sport" in the baby Impreza 2.5i is simply wheels, tires, and cosmetic fluff, NOT a different exhaust system. You can of course open up the center and muffler bores with aftermarket stuff, but be careful if changing anything up front near the heads as you may need to retune...as well have reduced low end torque, making the turbo lag and boost even less smooth. It's tricky stuff, and best left to WRX/STi specific hardware and management. Good luck, but don't overheat anything!