If you choose to go with the 215s, I suggest you mount front and back on one side and see how they look. If those are the wheels you like best, those are the wheels you should have on your X--best choice is your preference.

For consideration if you haven't already--All colors have a tint. Meaning there are green grays, brown grays etc. The only way to be sure you have a match is to see them against the color of your X (paint something and compare in natural sunlight and shade). To see which looked the best with sapphire black and the wheel trim on my X, I ordered a can of each of the grays from https://www.dipyourcar.com/home.php. I chose Anthracite gray with some level of glossifer as the best match and look.

I also checked the direction wheel colors are trending, doing so should provide some indication if black is on the way out. Black looks good to most of us. One reason is it has been out there longer, which tends to make the color less radical and more widely accepted.

'In' colors come and go. My unscientific take was that wheels are trending toward semi-gloss gray to blue gray colors. I suspect because there is broader market using neutral colors. That doesn't mean black is on the way out, it isn't. Black looks good with most colors and there is still a significant selection of aftermarket wheels offered in black so of the two what you like best is still the best color to choose.

FYI- after all that 'research' and having purchased what I need to make the switch, I haven't painted my wheels, not sure which is my personal preference.

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