Martin:

If you install a BT unit in an X3, the car needs to be coded to recognize the unit, or else the BT is not functional (assuming BT/Assist was not present before).

I've purchased a ULF -387 that I put in a e46 and the VR worked flawlessly. I put the same ULF-387 in my X3 and the VR is no longer functional. In addition, the car would not recognize the unit until it was coded. In addition, I do not have SA620