The answer is personal preference. Not that of those here but yours. My bet is you already know or you will know it when you see it.

My opinion is find one or the other with lowest mileage, one or two owners, complete history and service records where you have the option to purchase a warranty.

The strengths and weakness of comparisons seldom match up and many can be resolved with aftermarket upgrades. As an example, the E70 suspension can be upgraded to make it more planted. The Dynavin N6 will upgrade the E53 Nav and is offered with a optional backup camera.

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