If you want functionality, go with 4,300K or at least at no more than 5,000K, as the lumens (illumination intensity/strength) actually decreases as the color temperature increases.
If you want look than go with as high a color temperature as you want, but be forewarned that you will loose illumination strength, so why bother spending the money in the first place?
I have the 4,300K and could not be happier with the functionality and performance aspect of the HID PnP kit (even though it's in a 7 Gen).
