some HID questions, please help

I've been looking around for some HID kits to buy, and I really like the purplish look for the Stage II 6000k kit at http://www.hid4less.com. But their kit is $750, and from what I read most people on the boards pay about $450 for theirs. Why are these so much more expensive? Are the better quality, or just over priced? Also, I know that 6000k kits are supposed to be more purple, where 4k is more white right? Well what about the 7000k kits, or the 9000k kits? What color do they light up? Also, has anyone bought from xenonhid.com? That's where i found the 7k and 9k kits and was wondering whether their any good.

Oh yeah, one other thing. What's the deal with the low/high beam kit? I thought you couldn't have high beams with HID's.

7000-9000 I belive are blue, not too sure

4000K = blue/white
6000K = purple/white
8000K = white/white

Just look at some of your old highschool science books. Look at the color of the spectrum. It's all about color temperature. That's how they could tell what gases some stars are made of by looking at their color temperature. The lower you go the more cooler the color temperature 1000K and so forth would be yellow light. 10000K would be really bright white, so much so that putting it in your car would look like shit. You there would be very little light. The higher the up you go the less visible light you'll see. Therefore getting these really high HID kits 8000k and above would result in less visible light than your stock hallogens.