one more thing, you don't necessarily make bikes faster, just you. The best thing you can do for speed is a nice lightweight fork and some lightweight wheels (chris king wheelset laced to some Araya Super 7X rims with titanium spokes will rock your world.) Other piddly things like a lighter seat and some nice Tioga Comp III tires will help, as well as getting a narrower chainwheel and freewheel (or if you're running a cassette its no problem) and running a 9 speed MTB chain