I celebrated the Fourth of July by installing a set of HID lamps in my Lotus Elise. I purchased these a few months back from DaBears2K when he was offering them as a group buy on LotusTalk. The kit is from DDM, and is basically plug and play.
In the Lotus, you have to jack the front end up, remove the wheel and wheel liners, remove headlight covers and headlight assembly. After mounting the ballast, you just plug in the wires and reinstall everything. The first side took about an hour and a half, but the second side only took about 30 minutes after I had all the proper tools laid out.
I was amazed at the difference, before HID, the Lotus was actually scary to drive at night, the stock headlights were pathetic. Although Lucas, The Prince of Darkness, does not ride in the Lotus anymore, some things never change.