With higher lumens, those crazy kits 8000k-even 12,000k... visibilty is really poor-- especially in bad weather. I know because I have tried a few and experimented with them (thanks to a few other individuals that made me further my quest for HID knowledge):

I have tried/installed:
Osaram 6000k (Actually it's 5,400K), Phillips Ultinon 6000K, the Korean 5,400k, 8000k's, factory 4,300k...

I'm no expert, but honestly anything over 6000k will be very bad for visibilty. Sure it looks cool, but I wouldn't depend on them for driving.

4,300k was a standard that the light bulb designers settled on to be the best possible lighting... I think factory 4,300k works best but I would like a little bit of color to it.

And yes, you could transfer the kit over to your next car, just modify the base of the bulb. I plan on carrying over both my sets onto the next car...whenever that might be