I know this is a bit old, but being a Subaru employee, I figured I should throw my knowledge into the ring.

There's not really anything you can do for power on the 2.5 that won't lunch the transmission beyond a simple exhaust and high flow filter.

Erik P.
Official 2GNT thread Hijacker
Some say that he's driven over more Covenant than he's shot, and that his grenades aren't where you'd expect them to be...
All we know is, He's not The Stig... But he is The Stig's Spartan cousin!