Definitely go with the Philips oem 4300k.Always used this brand on my other non-xenon cars and their bulbs are top quality,especially their blue vison range,which I use on my X5 main beams.They are called "blue vision",but they emit a bright white light ....
If you buy from Ebay,just try to find a seller that has sold loads of these.rather than one that only sold a few.My 2 euros ,anyway