Well.... I've got 35w 6000k in mine. Looks pretty white. But all in all, ANY aftermarket HID kits are illegal, as they aren't self-adjustable. So I can if you put a set of 12000k, you will get more attention than 5-6000k. And you can get done for em, just because some haven't, doesn't you won't lol. But at the end of the day, it is pretty easy to disconnect and plug your normal globe back in.
The difference between 5000k and 6000k is not that noticable, but difference between 5-6000k and 8000k is pretty noticable. As for voltage, you wouldn't need the 55w kit, 35w is bright enough. More power it uses, the hotter it gets, and you wouldn't want to melt your headlights
And if you want, I can get you a pic tomorrow night.