[Ibiza]

I believe that's the only option, including the change in bolt pattern.

"The new X5 M and X6 M vehicles come standard with 21-inch M light-alloy Double-Spoke bi-color Style 808M wheels with 295/35ZR21 front and 315/35ZR21 rear non run-flat performance tires.

Available as an upgrade option on the X5 M and X6 M, and no charge option on the Competition Models, is a staggered 21-inch front and 22-inch rear wheel/tire combination featuring M Star-Spoke bi-color wheels Style 809M . Exclusive and standard on the Competition models is a similar staggered 21 inch front /22 inch rear wheel, Style 818M. Both styles of wheel come with Non run-flat performance tires sized 295/35ZR21 front and 315/30ZR22 rear."


https://www.bmwusanews.com/newsrelease.do?id=3503&mid=