Tried this conversion on a V class merc did one headlight first to compare - the pattern was great - really nice and bright. All seemed good until I looked at the car with the headlights on. The HID was dazzling at night - the original wasn't.
Yet on a bike (a BMW R1150GS - this isn't a problem.
Maybe the "Projector" style lights are better for them. The lights that you can actually see the filament of the bulb seem to dazzle more with HID's....
So tread carefully.....
M.