Hurdy, you're wrong, as I said above:
cars with bi-xenon headlamps by law have to have a sensor on the rear axle, normally factory fitted, which auto levels the xenons when the car is heavily loaded, otherwise you blind oncoming traffic.
theres a huge thread on this from about a year ago, where someone was going to retro fit them, and TT blew them out of the water, as he does know the law.