For $50 start with a complete tune up, so this way when you do get to modify it, you will get the best performance out of the engine. This would include, Plugs, Fuel filter, PCV valve, Use some good gas and Gummout Regane fuel system cleaner. Your first mod that is cheap should be either a Short Ram Intake or a CAI.
if you already have intake, m next step would be exhaust & then headers & cat..the exhaust will help w/ igh rpm hp & then when you get headrs, that will fill for low rpm trq & hp as well as high rpm power due to flow characteristics..
p.s. a 4-2-1 header gives more hp & trq in lower to mid range, a 4-1 will imrove hp & trq in higher rpm's from about 4500 & up...
want my altezzas? i'll get rid of them for $50 plus shipping costs. let me know. only problem is a tiny crack on the edge, near the side panel, but i covered that and the other side, for symmetry, with a white vinyl "A" for acura. they go for a bit more than 50 on e-bay. i'll link an auction with a pick of the kind of altezzas if anyone is interested (don't have a dc).