Oversize tires change the final gear ratio. Acceleration will be slower to some degree. Wider tires should be on wider rims to maintain handling characteristics. I suggest the H&R lowering kit and spacers. Doing both will get you where you want to go. There shouldn't be any difference in the ride quality as the lowering springs are the same spring rate as stock. It is also the least expensive route. After you have installed the springs and spacers you will need to get an alignment.

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