Right, so im currently in the process of buying a salvage a3 which has factory fit xenons. Being salvage one of the headlamps is ok, other not so good, bit out of shape and would need changing. The cost difference between me buying bi xenons and a normal xenon is next to nothing.. But what would I need to make the additional feature work? Is there sensors to operate the left and right movement, or is it based on the steering? Are the ballasts bulbs etc the same? Any info would be highly appreciated.