hey i have a 325ia convertable and its really slow its an automatic i have custom exhaust (http://forums.bimmerforums.com/forum/showthread.php?t=1027685#) , bumpers , paint , and audio set but

what i need to know is how to increase the horspower and make it faster

i have about 4000 to spend and i was thinking bout puting in a new engine and a turbo? (would an m3 engine fit and would it be crazy?)

also is you guys have any tips how to make it faster for cheaper im all ears