Serge had some 4300k HID bulbs for sale not too long ago and I had some HID Ballasts in the closet so I figured I'd stick em in my reverse lights in the Avalanche. All you need is some double sided 3M tape, two HID Bulbs, two HID ballasts, some high temp silicone, and some electrical tape. Here's how to do it in 5 extremely easy steps:
1) Take out reverse bulb and cut the two wires with the female plug attached to it (it will be replaced with the black and red wires going to the HID ballasts).
2) Take the black and red cable that attaches to the ballasts for power and cut them off along with the male plug.
3) Strip down the 4 wires that are now cut and splice them together (either with electrical tape or solder it): black goes with black (ground/negative) and the red goes with the other loose connection (mine was white, but I am running an aftermarket LED tail).
4) Trim tail socket to fit HID bulbs (I had H11's which does not without modification FYI) and seal the surroundings with high temp. silicone.
5) Clean off the ballasts and the spot where you will tape them down at. I did mine right on the inside of the truck bed. Put double sided tape on the ballasts and tape it to a spot where you know won't be too tight of a fit to where the tail lights will not get in the way.
Results:
Night pics: