What car do you have? The question is when getting HIDs are, "are there any quality projectors out there for my vehicle?"
If not, you'll have to look into doing a retrofit, which will take time and dedication - however, you can get better results than many "pre-built" type solutions. Most eBay solutions are bunk and low-quality.
Regardless, I forgot the exact forum, but I believe its the forums at
HID Retrofit Parts Projectors Ballasts D2S Bulbs for retrofit information.
Obviously, I say all this because you don't want to throw HIDs in halogen housings like ricers do (this isn't even limited to the import crowd... I see plenty of HIDs in halogen housings on pickups and other domestics as well... I call it "American rice").
It's a danger to everyone else on the road, and you'll probably get worse performance than with just plain halogens as far as lighting up the road.