uhhhh, guys, it's called Nitrous. not NOS!!!!!!!
NOS NOS NOS NOS NOS NOS NOS!!!!!!
anyway, on the stock internals, you can run up to 50 shot, depending on the wear of the engine. How many miles do you have on your car? Also, as for what it does for you performance wise, alot. It is definitely the best "bang for the buck" performance mod.