Radar Detector Power
 

I just installed a Valentine 1 in our new 2009 X3, tapping the mirror power lead, so it's mounted high on the windshield, near the mirror. It was easy to do this once I found the right wire (using the online wiring diagram system at WDS BMW Wiring Diagram System - English) which is the green/white in the bundle going to the mirror. (If you don't have the photochromic mirror with the universal remote and compass, the wiring should still be there and be live, I believe.)

There are more details in this post:

Radar detector power - bimmerfest - BMW Forums

DrTom

I also posted in the thread on Bimmerfest, but THANKS to DrTom for writing this up.