I would like to know this as well. Don't you need a ballast n whatnot for the HID bulbs??If you can find a way to properly aim, then I think these are worth it. For people who have HIDs in them, if I'm reading the posts correctly, I can just plug my bulbs in from Diode Dynamics w/o the ballasts and everything will work fine? If so that's awesome, gonna do that, but taking the spec-d housing out is such a pain...