This is the message I received from EDwinter when I tried to reserve tires for the M5 a little while back:
I am sorry but we do not stock any Winter tires for the M5.
In fact, and I'm not sure why, but we are told there are none to be bought
anywhere at the moment.
Regards
John
www.edwintertires.com
I have a contact looking into this at BMW NA, and if I get any information I'll post...