Ok, first off I can confirm that the stock low beam housing will not work for hids. When I just put mine in, I did the whole blind/**** off other drivers thing and I had to go getto rig up a shield over the headlight that only let part of the light out. This really surprised me how well it worked, but by "worked" I mean not blinding other drivers, not giving me great wonderful light on the road. I live in a pretty urban area however so I really don't even need headlights to drive around a night, so this was really a temp meassure untill I can get projectors installed. Now, I cannot stress this enought that you need to convert to projectors. That is the only way to get both a good light pattern so you can see and to not blind other drivers.
Now as far as the high beams go, its really up to you. I'm leaving mine stock halogen, just cause its easier and I've already droped enough money into this project. Since high beams are intended to be used when theres no on comming traffic anyway, you could possibly get away with just sticking hids in there without a projector retro fit, but thats not really advisible. Hids really don't like to be turned on and off quickly, so if you did hid high beams you'd loose your ability to "flash" alert other drivers (well, not loose per se, but it is really not good for the lights to be doing that).
Now in terms of am I satisfied with doing this.....right now...not really. Without projectors I don't really get a lot of light were I would need it on the road so it makes night driving a little harder. Now once I get the projectors in there, its hopefully going to be like night and day and I'll be kicking my self for why didn't I do this sooner. So I can't compleatly answer your question on that one.
So, to recap my little essay here:
1. yes you can convert to hid lights, but you need to have projectors with them
2. hids for high beams are not advisable, go easy on youself and keep um halagon
3. brands and cost.....yeah, um....you get what you pay for. Cheap kits and cheap projectors will get the job done, but may burn out quick and give you a crappy light pattern. Generally if its not the same thing that an oem(think mercedes, bmw)would use, then I'd question its quality and reliability.
Whew, sorry if I rambled on there or sounded a little harsh at times, but its just that I've been struggleing trying to find time to work on this for what seems like months, and any project that drags out that long you kinda get that what the hell was I thinking attitude.
Oh well, I wish you the best of luck man and I'll be sure to post when I finally get everything in there (I'm shooting for a week or so from now, so I'm close).