I just installed a pair that I received over the weekend. For some reason, it looks like all of the "euro" mirrors are shipped out of Eastern Europe. Took about 2 1/2 weeks for them to arrive, but I am a very happy camper. I've had these things on all of my BMWs in the past, but nothing needs it more than the X5. Now I can see small, low cars that are next to me and cars 3-4 lanes over!
There are plenty of them for sale on eBay and they come in the auto-dim/heated variety, or whatever your car is optioned for. Don't understand why our cars don't come with these in the US... it is very unsafe to have to turn your head while making a lane change at highway speeds.
With that said, I have a pair of mint US auto-dim/heated side mirrors for sale if anyone needs them!