yeh you selling any HIDs?
In theory if you get a set of HIDs, you will need a ballast too. The ballast will regulate the power flow and *should* prevent any bulb out error messages. You can buy canbus-ballasts and canbus-hids, but I have a ballast and HIDs and they work fine.
If your looking for whiter light, you'd need to go towards 5000k as 6000k+ you get the hint of blue.....
I get stuff from HID Direct. No issues so far. X2 ballasts and X2 HIDs. Ideally if you have reflector lenses you'd look to get H7R HIDs as they are designed for the reflector lenses and will pass the MOT. Normal H7 HIDs will of course fit though but may blind people a bit.
I've had no issues at all with my HID in my ownership. Never changed the bulbs yet although I will be soon as one bulb has gone off colour. I am planning to put light tints on the headlights so we'll see how that goes!