If you have factory xenon then you can change lamps to 6000k no problem there. You can get problems if you go from stock 35w to aftermarket 50w, make sure your lamps are 35w, color temperature does not matter. As for the fogs, since there is no factory xenon there you will most likely nead the aditional cable or make your own with resistence and relays

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X5 4,4i-06 Current
330Ci Cab-03 2007-2008
MB E55 AMG-03 2006-2007
Z3 2,8 Roadster-98 2006-2007
X3 2,0d-05 2005-2006
320d-99 1999-2005