4300k for the win.
Also, generally speaking, with ebay HID stuff the wattage listed on ballasts is the input wattage, and includes ballast inefficiency.
also, can anybody say boost driver? 85V nom output, 24000v on startup
last, be wary of UV. Sometimes, bulb makers will slack and not make the outer envelope out of UV absorb, but out of regular glass. This would still probably be just longer UV waves, but it still may be present and possibly dangerous.
I've been wanting to just get a cheapo spotlight and drop in a cheapo 55W kit, but I don't have room for something that bulky, nor a need for something that throwy. The cool factor in these firefoxes is that they are standard flashlight shape, extremely carryable, and spit out more lumens than most cars' headlights (yes, plural, both headlights put together).