Im pretty sure its not possible to like a 5 series with a kit more then an M5. Its the same thing except the M5 has an ///M engine and more sportier.
Yes I did rent a 09 550 with an M kit but I didn't drive it much. I drove the rented Range Rover Supercharged

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2011 ///X5 M (On Order)

2009 X5 4.8 M Sport Space Gray/Black Fully Loaded

2007 GMC Yukon XL Denali Loaded and Customised