Ran across this interesting Pelican thread while pursuing an upgrade involving swapping my "M" calipers for "A's", with 84-89 struts and rotors. Anybody swapped an M caliper for one from a BMW? Awfully cheap, and gets you everything you get from the Carrera swap except the 20% thicker rotors.

http://www.pelicanparts.com/techarti...W_calipers.htm