I have a set of Revolution RFX, and a set of Kosei K-1 Racing, both in 15x8". I think the extra width helps in performance. The RFX is 20mm offset, and the Kosei is 22mm. This is the fitment for the E30 M3 in 15x8". (You may have trouble with the stock 7" M3 wheels, as they are 30mm or something like that. I can't advise you on that question). The 15x8s both run fine with Yoko 215/60-15 tires, but I need 5mm spacers up front to run 225/50-15 Toyo Proxes on the track.