WheelSto, Tire Rack, IND, GTMotoring, plus others shown in sponsor section:
I bought my wheels from wheelsto and was happy with their pricing and service.
'04 E46 M3 - Jet Black - Sold
'08 E90 M3 - Alpine White - Sold
'13 E92 M3 - Silverstone II - Sold
'13 E92 M3 - Alpine White - 1 Option (DCT), Ohlins TTX, AP Racing, Cobra Seats, Akrapovic GT4, BBS E88, Volk TE37, M3 GTS - Steering Wheel, Aero, 1/2 Cage, Seat Delete