I have a nice set of BBS CX-R with Antracite/ Machined Spokes for sale. They come with tires, which may or not fit m3:
20x8.5 ET25 Front with 245/35/20 PS2
20x10 ET25 Rear 285/35/20 PS2
I was running these on my CTS-V Coupe (yes they are compatible between the two vehicles). They will require new hubcentric rings, which I will provide from BBS, at the time of sale.
Asking $2100 shipped within the continental US. Email me richp AT rtechnic DOT com, thanks!