It's my understanding that while it may be inconsiderate to other drivers to drive with your high beams on, it is not illegal. It is however illegal to flash from high to low (or vise versa) at oncoming drivers for any reason whatsoever. It is also illegal to have any light on your vehicle emitting anything close to blue light…as it a reserved for police and emergency vehicles only. I have heard of many getting tickets for having both non "DOT" approved headlights and for using the reserved colors.
Back on topic though…I personally think that the HID junk kit's they are selling everywhere look like **** unless installed in a properly focused projector housing.
Also, anything past 4400K is pointless as it shifts to the less visible blue spectrum.
Stealing some pics from a board member…you can see what HID's look like when simply thrown into a standard reflective housing.
Notice on the intense glare and the lack of any type of beam cutoff.
Compare the previous images to how the HID's are supposed to look...
Notice the cut-off line which has no light above it?
Anyways, here is a link on the proper way to retro fit a HID assembly… http://forums.stangnet.com/showthread.php?t=670834&highlight=retrofit+hid
…and another link with some good information on HID's in general… http://www.danielsternlighting.com/tech/bulbs/Hid/conversions/conversions.html