I have just moved over to a 1M from a 135i and am looking for some aftermarket wheels. On the 135i most people went for 18" wheels with 1" wider on the front and rear. There was a well known size and offset that filled the arches nicely but ensured there was no rubbing. The offsets were "8.5 ET45" on the front and "9.5 ET50" on the rears.
Is there a pretty common size and offset people are going for in 19" wheels on the 1M that fills the arches nicely but definitely wont rub?
Something like this would be good
http://www.1addicts.com/forums/showthread.php?p=9768501