i have a turbo supra and the first thing i did was throw on a 3" exhaust, downpipe and high flow cat and muffler and that stuff helped out dramatically!!! I think that's the way to go, except for a header....my exhaust setup has cost me something like $150. That is way cheaper than any exhaust setup that I have found anywhere! i'm tellin you...build your own exhaust...it's worth it(and it's easy)!!