my suggestion is to do coilovers because of the adjustments (height, compression, rebound) this way you can do the rims later and fine tune the ride you want to have (stiff or comfort would say from experience in the business i would have to say that 75% of people that buy just springs end up buying coilovers anyway
and prices:
http://www.e90post.com/forums/showthread.php?t=24934