55watt HID kits will be brighter than a standard 35watt kit, but you run the risk of burning the projector bowls which after extended use lead to diminished light output. I always suggest to go with a 35watt kit to play on the safe side.
6000k will be blue, but will have less actual lumens output than that of a 5000k or 4300k bulb. I personally love the pure white output of 5000k bulbs. Fog lights (if you use them for functionality instead of just for show) work best in the 4300k to 3000k range. Those color ranges actually pierce through fog and rain and allow you to see what is in front of you. 5000k and up bulbs tend to reflect more off of the fog and rain causing a washed out glare to your own eyes. As for HID vendors, HIDExtra is ok, but if your patient and have some extra coin to spare TRS is coming out with newer ballasts this or next month that fix all the issues people have been having with them. Still though, its down to your budget as the TRS Moromoto kits are spendy.
I've got an extra paycheck coming in this month and I'm contemplating the Morimoto Mini-D2S Quick-Retro kit for my 2012 xb. It comes with new projectors, ballasts, bulbs, harnesses/relays and a laser cut mounting bracket for everything. Looks like the hardest thing about the Quick-Retro kit is baking the headlight housings to remove the lenses so you can get to everything.
sorry for the late reply, after work I just tend to be too tired to do much, I'm primarly looking to have all the lights on the front of my B be more or less the same color temp, though I dont mind the fogs being more yellow if that helps in the fog and rain, so whom to get HIDs from if not HIDExtra? and I would rather not have to take apart the headlights if I can help it.