If the black intake scoop is missing he probably saved you the 15 min job of gutting the intake. If it doesn't already have a k&n or perrin air filter get one (got my k&n at autozone for $42). Spend the rest on a STAGE I ACCESSECU from cobbtuning ($395). This would net you like 265 crank hp or ~+35hp. Best bang for the buck with 450 bones. According to the upgrade path listed above in my previous post, you would just be getting #4 & #5 from the list. Doing those two would be called either a stage 0 or stage 1 if you researched different tuning company's websites. Doing steps 1-5 would be a stage 2, and 1-10 stage 3/4. Only prob with getting engine managment first would be that once you finished 1-5, you would want to get the car retuned again, so you are paying a bit more, but if don't plan on getting alot of money for a while, it's worth the power. Like mentioned before, don't take the boost controller / s-afc route. Boost controllers and simple fuel controllers don't work well with the subie ecu and also encourage you to turn up the boost and blow your motor. Do it right the first time and get the ecu flashed or get UTEC, both of which can be set up so that the dealer can't recognize them too.
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02 WRX
K&N, ic hoses, up-pipe & turboback