first off, dude you have a bad brand of ballasts. They don't carry a good reputation for life of their expectency! HID bulbs light differently as they age. So if ur looking for bulbs, look for 2 bulbs..cus the hours used on that one bulb will make your plug+play kit into a total multi-colored venture. I would suggest you to invest in genuine OEm ballats (hella or phillips) and then play with those. It will be more expensive up front...but cheaper in the long run!
it is the plug and play from mcculoch and i only used it for bearly a year. they seem to be a popular brand and i was disappointed. anyway what kind of bulbs will fit this particular model? i got everything except one blew bulb.
The color temperature is determined by the specific chemical composition inside the capsule (and sometimes a blue coating on the exterior glass), not your ballasts or ignitors.
So yes, you can use any temp you'd like... although 4100k is OEM and puts out the most light on the road. Anything else is just for looks. If you've seen the guys with purple HID's out on the road, you'll notice that they're blinding but have virtually no output on the ground in front.