If your X5 was produced after April 04, you won't have the sunglasses holder. I don't think you can retrofit it because the place where it used to be is now housing the interior motion detector. But if you don't care about the motion detector, I don't see why not. You might get false alarm codes (???).

But if you are still looking for the part #, go to the link below and look at item #5. There are different part numbers depending on the color of your interior headliner. The bad news is that you can't just get the sunglasses holder by itself, you will have to buy the whole overhead console. As you can see from the diagram, the sunglass holder is now replaced with a cover (item #24).

Here's the link: http://www.realoem.com/bmw/showparts...00&hg=51&fg=55