Best results I have had is using Dr. Colorchip. At least silver and black are great matches. The process to smooth out the paint really helps hide the repair. It is necessary to use very little each coat and build it up. I've tried using heavier coats and ended up starting over.

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X5 4.6 2002 Black Sap, Black interior. 2013 X5M Melbourne Red, Bamboo interior
Dallas