a 8000K is going to be a blue tint, with less light output than the 4000-6000K kits.

4000-6000K is a nice white, with almost the best light output. The higher in lumens you go, the less light you get but the more color. So it depends if you want more light or more color.

They will last just as long as your car does if you wire them correctly. When I had them in my car last year, they were spectacular. I had a 6400K kit and it was a nice white and a shade of blue tint. The output was really good for me, and I didn't even adjust them until I sold them.

They won't hurt your OEM switch if you have the relay wired correctly, and they pull less power than OEM halogen bulbs. I can get you an HID kit if you need.. PM and I'll give you details on all the kits I sell.