I have it and like it. It helps in parking and slow speed manuevering. However, I do think there is a slight trade-off in steering feel at road speeds. Just depends on your preference. As others have said, try it out (although, in my experience, it's not a real popular option and often hard to find one with it on the lot).

Also, as Craig said, it's not available on the diesel model for some reason.

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2008 X5 4.8i, Jet Black, Tobacco Nevada leather & just about everything else (no vent. seats, no 3rd row)