i would also reccomend a header. It made a massive difference all round for me. I just got an .18 size one from my lhs that fit. I would also reccomend getting it fully ball-bearing'd so that there is less resistance, and also cause the bushings that come with it wear down the axles. And if you can still afford it, perhaps a better exhaust pipe. The ball bearings made the most noticeable differnce for me.