The easiest and cheapest way in my opinion would to but an Element High Speed motor
http://www.khmountain.com/airsoft/pr...oducts_id=1418 and an 11.1v lipo. This should get you shooting at at least 35+ RPS and should only cost you $60ish dollars. If your gearbox has stock Chinese internals, your piston will certainly strip before you are done your first game. You'll also realistically need a MOSFET since your contacts will start to wear out VERY quickly on an 11.1v lipo. And you don't want to run a sub-300fps spring because the gears will be spinning very fast and the spring is not stiff enough to return the piston back to forward position, thus causing your gearbox to explode (or something like that). Thus, you're gonna have to spend a lot more that $60 to buy good internals that can handle the RPS of a high speed setup. And I just realized that most of the things I've said was covered by Kos-Mos.
