To sum it all up.... if you are running 10K bulbs, you are a lot more likely to get pulled over. Plenty of people run HIDs in their stock housing, which Bio pointed out blinds the **** out of people. To safely and get the best light output is to retrofit your headlight housing. With a projector, the cutoff line with a 4300K is blue, but the light output is white. 4300K is what almost all OEM projectors headlights come from factory. This gives you the best light output, which is what lights are meant for. 6000K is about the limit you should go for visibility issues. 6000K has a light hint of blue to the light output, cool blue like Bio stated. Anything outside of that is no longer sufficient for increased visibility, let alone distracting to other drivers. As for the people who said their 10K isn't blue, I guarantee you they didn't get the right temperature. If you buy cheap ****, the quality is lacked thus the light quality is lacking. You want an HID kit that performs, get a Morimoto HID kit. Have nothing but perfection from this kit, and would buy another. They can be picked up over at the retrofit source for ~$150 dollars.