[Mr. Blue Sky]

One thing that hasn't been mentioned here is that in most cases, the HID kit bulbs are just 35 watt bulbs that are being overdriven to 55 watt or whatever by the ballasts(if you don't believe me, then try the same bulb with a 35 watt kit ballast and see that it light up fine). Original 50 watt bulbs like the DL50's from phillips germany, that are built to run at 50 watts cost a lot more and last a lot less than 35 watt bulbs that can be overdriven to 55 watts. Another big issue is the heat that is created by them. From what I have read at hidplanet.com, Kit bulbs do not have the same thickness of the UV reflective glass covering the bulb, which can later cause the chrome of the headlight to get damaged.

If you are going to run it on reflector setups, there may not be as big an issue with the heat, since the bulb has some space between it and the closest part of the headlight, and is more open to the air. This issue becomes more of a problem in most projector housings(like the H3 halo lights for our cars), which tend to have closed in projectors and sometimes have small reflector bowls, which allow buildup of heat. That is why even though I am also running 55 watt, I am running a genuine phillips d2s bulb, with retrofitted projectors, which will cause less heat than kit bulbs. Just a thought.