I did a lot of research before making a Kelvin selection. I wanted the most light WITHOUT having glare. I wasn't looking for purple or blue... I wanted pure white with a clean cut-off; meaning that the edges of your light pattern are crisp. Everything I read pointed to 5800k (or 6000k). Everything I read also indicated that 8000k, 10,000k, and 12,000k would give the complete opposite of what I was trying to achieve... you'd get glare because of a harsh cut-off. The harsh cut-off is not only bad for your eyes, but it's bad when it's raining, AND it pisses off oncoming traffic.
I'm not claiming to be an expert in HID. I have a 6000k kit in my Explorer and my Busa. And I'm not putting down anyone who has chosen another Kevlin. I'm only going on my personal experience and from what I've read. Some people prefer the yellowish tint of 2300k, some people like the bluish tint from 8000k, and some like the purplish tint from 12,000k. I went with pure, natural light.
By far the best site I found for HID information and pictures confirming the 8000k, 10,000k, and 12,000k glares and harsh cut-off is