I've got a set of LEDs coming tomorrow to try in the mains, as i don't like the yellow.
Further to dubber 36's comments above, lighting is what I do, and the higher the colour temperature, the bluer the light output and less actual visual spectrum for the human eye to pick up.
In short, the bluer the light, the less it lights the road in front, so going lower in temperature can only be a good thing.
Certainly don't go above 5000k. Car Rover offer an 8000K kit, ok, but not recommended.
I'm interested to hear the results from dubber36?
I would not recommend HID in main beam, if you have main and dipped stay on at the same time, that's a lot of heat in a plastic lamp casing, would you agree dubber?