They don't have a bulb housing, you would have to pick that up somewhere else. The HID kit was about $30 with $10 shipping. http://www.ddmtuning.com/JP Cycles and Nfieldgear both cary Adjure headlamp housings they run $80-$100.
I am hazarding a guess that routing the on-off power surge through the bar switch is doubleplusungood, so thought a relay was the best plan.
Only weird thing I can't figure out is whether the bulb itself is oriented properly. The filament (or whatever it is in an HID) has a little reflector opposite it.
Mine worked OK for the year or so I had it. Bike has been in pieces and transport since last July and I'm rebuilding it with an H4, simply because I want to be able to deal with problems that crop up here in the third world quickly and easily. Bulbs are easy to change and spare H4 sockets are easy to swap in. I also think it'll be nice having a low-hi beam choice again.Small thing I didn't like was the warm-up period, but that's really no big deal.Edit: The reflector location problem I had mentioned above was silly--the bulb does need to be correctly oriented, but it was simply rotating the reflector which fixed it.