High Beam Assistant (Auto dimming headlights as you call it) are not in the US model. High Beam Assistant turns the high beams on and off automatically as on-coming cars approach and pass. I have no idea why they didn't include this feature. It should be offered in a car of this class.
However, Adaptive Headlights (headlamp tracking as you call it) works fine in my 650i. Make sure your light switch is all the way to the LEFT (green LED light will come on near the light switch). It will NOT work if the switch is all the way to the right. Then drive at night on a dark road and weave your car back and forth a bit. You should see the headlight beams moving left and right. If you don't, it's broken. Take it to the dealer for repair.
Last edited by INTREPID; 11-24-2005 at 05:16 PM.