I picked up my M3 (new style) rims from Kal-Tire.
Decent value -- on sale -- net cost (tax, balanced & mounted) with Nokian NZRi summer rubber was about $2200.
Came with BMW centre caps.
(I couldn't really get them cheaper -- since on the web theres shipping and then you probably need to get them balanced etc.)
In addition, Kal-Tire will swap my summer and winters for life. And if you ever get a puncture they fix it for free (I got a screw in the tire a few weeks later from a construction site near home).
Anyway, I am happy with them.
The manager said that they come from the OEM factory (Italy or Germany) and that the quality was top.
Hope that helps.