I highly recommend getting a 1/2" Torque wrench if you do this. If you watch, Sears usually puts them on sale every once in a while.

While not necessary by any means, one of these tools is handy to align the wheel since BMWs use bolts, rather than studs and lug nuts:

http://www.reverselogic.us/ReverseLo...M14x1.25_1.jpg