If you have a 5th Gen. Prelude, IMO a header isn't going to do much for you for the amount you pay. If you look at your stock header up to an aftermarket header, they are pretty much the same size, so you're not really doing much there. The most hp you're probably get from a header is anywhere from 2-3 if that. As for exhaust, maybe look into Greddy Evo or even Mugen.