I'm sorry & not trying to be an ass but don't ever get 8,000K HID's, it's pointless and you might as well convert your headlights & foglights with Silverstars halogen and be done with it. BMW's and high-end vehicles "do not" have 8,000K look, it's all 4,300K with the projectors that makes various colorful output in a different angle. If you ever driven one or sat next to it, the actual light out put is 'white'.
The maximum you should go with is Philips Ultinon 6,000K. But it's best to stay with 4,300K. I would highly encourage getting the OEM Philips/Hella/Osram with projectors like Bosch/Valeo and either modify your current housing or if not buy an aftermarket headlights & install them there. It's not pointless but if you want a sharp crisp light utilizing as much light as possible, the projector/OEM HID is the only way to go...