Finally a topic I know a thing or two about :smiley:

Are you planning on modding existing headlights, building a new set or buying new ones? First of all, from my experience the technical requirements within a vehicular environment are very different from a flashlight. Factors to consider are i.e. heat cycles, NVH, shock resistance, road worthiness, technical approval measures (DOT/NHTSA, E-mark, TÜV, others, …), and how light behaves in a traffic scenario (very strict tests and approvals are done for them).

If you want angel lights only (the halos) for your existing headlamps, there are kits out there specifically for cars and trucks. They come with full connectors, ballast, harness and potentially resistors or anything you might need. It is up to your jurisdiction to see how legal that set would be. These kits are probably more cost-efficient than building your own halos from scratch.

Otherwise there are also aftermarket headlights for your car as full lights. They have all kinds of features depending on how much you’d like to spend and they are typically tested and DOT approved.

edit:
For the BLF fellows who have never seen these things:

The “original” angel eyes, the variant that started it all