Very rarely have I liked the looks of the car with a painted rim. The color combo should work for the whole thing to come out right. I also suggest some photoshop to get your look first. (Check tirerack.com and see if they have your car's color, and try various wheel colors on it just for comparison.)

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Currently driving: 2011 E70 x35i , 2011 E90 335d
Previous BMWs: 2007 E90 328i , 2005 E53 3.0i, 2011 F10 535i (6spd manual)