I've been reading about HID's too. One day when I have an oven that actually works I'm going to open up my headlights and put in those FX-R HID retrofit ones from 'theretrofitsource'. All up including projectors they are going for less than $500 currently.
Google it, there's a guide on how to do it from one of those UK skyline forums.
Either that... or i'll buy cheapass $80 HID projector kits off ebay and retrofit since the car is getting old and is a real moneypit haha
My previous car was a mazda astina I had ebay $60 HID's in it with the stock projectors and it was perfect
I would not recommend HID's in a reflector type headlight, glare like anything.