I would be looking at the written regulations rather than just asking the nearest law enforcement officer. There will be written rules in the states codes. Look them up or enquire at your roads authority.

Generally the heat limit is 4800K.

HID's generally require self leveling and washers to be legal.

Higher Kelvin range enables you to see better in the range of the headlights. The tradeoff is that you are blinder to objects outside the headlight range.

Ever wondered why infra red is a cool heat range and lets you see in the dark?