I know this was from a long time ago, but the STi makes 300hp and puts down over 250 to the wheels stock and that's here in hot humid TX, and I know this because a friend of mine had his dynoed 2 weeks ago on a Mustang dyno. The Evo makes 280hp. The STi is also heavier, yet faster than the Evo. Good luck on this project, it will be sweet when you finish it up.