If you're interested... I did a comparison between some different colour temperature lamps in my HID projecstrs earlier this week. Bit of a boring subject, but I thought the results were quite interesting. I recently tried some 6000K lamps, just to see how they performed after my tired 7-year-old 4300Ks. Initially, the change looked quite impressive. The light output was noticeably better, and the way they picked out reflective road signs, particularly on open motorways, was very good. However the way they lit the road surface was not so impressive, and although it was better than the old 4300s I felt it was still a little lacking. So I got hold of a set of 5000Ks and set up a little experiment. I waitined until night time and set up a light meter about 4 metres in front of one of the headlights. With the 6000Ks still in, I fired them up and gave them 10 minutes to get fully up to working order. Then I took the reading. Next, I put back in the old 4300s, and again took the reading after letting them warm up properly. Finally I put in the new 5000Ks and let them burn in for an hour before taking a reading. The results are as follows: 4300K - 635 lux. 6000K - 786 lux. 5000K - 1024 lux. I was aware there would be a difference, but the level of difference was quite surprising. The moral of the story? There are two: 1. Blue might look 'cool', but it's ****** useless for lighting your way! 2. Old HIDs really drop off in performance over time.