don't throw an american V8 in it, that's freaking terrible. i bet that 2002 doesn't handle for piss....the best mod for those cars (2002) are the motors out of the 320's or better yet the first gen M3 motors.
want a sweet motor for your ride check this out:
my little swappage
but basic stuff to make her move.........i recommend a lightened flywheel (those motors take forever to rev up. you can have a machine shop lighten and balance yours for pennies on the dollar compaired to an aluminum/metal one). better exhaust (get rid of that cat if your emissions laws will allow you to do so, ie you are old enough where you don't need to have the car tested). reduce your accessories, drop the a/c and get a manual rack if you have power steering....the less the motor has to turn the better. frees up more HP and also aids in quicker revs.........cam is a pain in the arse as you have two options to install, 1)removing the radiator, hood, etc. as the cam pulls out the front of the motor......or 2) all together removing the head. and if you opt for option two i recommend decking the head for higher compression while it's out. i know there are some CIS tricks that i am forgetting right now as well........