The offset will change with wheel width. A 7'' wheel will have a different offset than a 7.5" or 8" or 8.5" wheel. Just make sure it is for a 3 series BMW and you will be okay. Second vote for no more than 8.5" wheel.
1995 325I, window tint, K&N, debaffled airbox, BMW #104 wheels, Nighthawk low beams, smoked side markers, smoked corners, smoked taillights, M3 stlye heated mirrors, various interior bits, Bosal cat-back.