what size, bolt pattern, and offset do i need to look for when getting aftermarket wheels to fit a 2002 bmw 325i with sports package exactly without having to buy new wheels?

Look in Roundel, the BMW Car Club magazine. A couple of big national tire store chains run special ads featuring European-made replicas of BMW alloy wheels. My wife wanted BMW Touring-style rims for her E36. Dealer prices were up to $350 each. I bought a set of FOUR for $440.