You also have like 350 more horsepower in you car than any normal 328
Listen to RYANMCELL, he hit all the major points, and check out bimmerforums. Lots of great resources there.
… i finally let my girl drive my car today, so im sure my cost of ownership will be going up
but
e46fanatics.com is another great forum to check out, i find myself on it alot now just reading stuff.