My "new" C5 came with the blue tinted headlights - they appear to be non-HID types (didn't even know there was such a beast!). I haven't seen any ballasts or special harnesses.

Unfortunately, the left low beam must have popped and the seller just popped in a '"regular" yellow halogen bulb in its place. Strange looking to see one yellow and one whitish-blue headlight!

The bulb(s) don't contain any temperature info so I can't match color based on that (lowbeams are HB4 9006 and highs are HB4 9005). So unless anyone has a great idea, guess I'm stuck replacing all 4 to insure a match?

 

I would just buy true HID lights. It looks better anyways.