Got the mirrors form ebay 2 years ago.
Couldn't find the seller as I have colsed the account.
I also looked on ebay and the net but no luck.
Mine look like these M5 style:
http://www.eurocarmotorsport.com/Image/a04.jpg but of course not OEM or else they would cost as much as my car
Despite my bodyshop guy trying to convince me to paint it all blue, I left the bottom part unpainted (mat black)... looks killer actually.
IMO better than OEM or M3.
PS: If you buy aftermarket mirrors, make sure they come with the mirror motors.
These did.