If you drop the sport package and willing to pay extra $4-5k, I think you should be able to purchase a brand new one with fresh warranty coupled with lower delivery cost. Of course that's assuming that this used X5 price is firm which we all know that's not likely. So, I think the answer really depends on how much discount you can get on this one. Just my 2 cents.

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2011 BMW 740i
2011 Toyota Sienna Limited
2008 X5 3.0 Space Gray (sold)