I know a good one in Detroit if you don't want to go farther north. Two brothers from the old country - cash only. Seriously, they are good - BMW only.
J & N Industries
Ask for Louie or Mike
(313) 366-4310
5431 E Davison St, Detroit, MI
Also try this web site:
http://motorcitybmwcca.org/index.php?action=forum