BMW always uses 4100-4300K bulbs. Nobody uses 6000K bulbs from the factory. The light color is dependent on housing optics only. D2S/D2R has nothing to do with bulb size. D2R bulbs have a band across the bulb to cut off some of the light pattern cause these were menat for reflector housing units although most people just get d2S anyway. I have d2S 6000K ultinons on my MDX(reflector) and they work great and have never been flashed. I also had 6000K HID on E36M3 with euro ellipsoids. I had HID on E46 M3 but upgraded to 6000K bulbs just for looks.choi0706 said:yeah the higher you go in temp (k) the less you see of the road. I'd use 4300-6000k bulbs nothing over 6 cause it usally looks purplish 4300k is white and is what most lexus cars come with.
I believe bmws come with 5000k or something higher than 4300k.
also if you look at cars that come with HIDs they have a reflector inside to make sure the bulb doesnt go everywhere i dont know much about this but i know they are different from halogen housings. Also picking the right bulb size makes a difference also like D2S or D2R