Just to warn you guys, DOT approved just means that it won't do harm to your vehicle. Look for 50 state legal.
I had an argument with a fellow locally to me, that worked for a HID retailer/installer. He said that they were street legal. I told him they aren't... His logic is because he got a ticket and then he asked the clerk to present his with the document that says why, clerk couldn't find it, so it was thrown out... rebuttals went back and forth and I presented this.
http://forums.officer.com/forums/showthread.php?t=41131
and this is the actual document.
http://www.nhtsa.dot.gov/cars/rules/interps/files/21118.ztv.html
These are federal standards (50 state).
summaries to the parts that applies; its legal to fit NON-Halogen bulbs into a halogen headlight/housing.
Not in the documents, but under the car manufacturer regulations: HID headlights can be no higher than 4200k.
Just keep this in mind