This may not be the help you are looking for but here is my 2c, the shop I use (Hattech car styling in Kitzingen, Germany http://www.hattech-carstyling.de/ ) (SHAMELESS PLUG) does a lot of M3 type mirrors both with and without the blinkers and it depends on the company that makes the mirror. I know that some will work as a direct plug and play so to speak and others are more complicated but ALL lose some features. The two they mostly sell are Hagus (non blinker) this is the more costly one and everything works except the heating feature the other model which I can't remeber who makes it sorry, has the blinker and as I remeber we had to get the wiring diagram from the dealer and then re-work some of the wiring to get it to work.