[tjts1]

Originally Posted by ceej

There is a great deal of information on automotive lighting up at this site:

Daniel Stern Lighting Consultancy and Supply
CJ

The information on his site is out of date. A lot of new cars today use exactly the same projector or reflector for both HID and halogen bulbs. Take a close look at a mazda3 or sonata or second gen prius. The parts are identical.