Why not consider the 35d? You get power like the 4.8. Plus the 4.8 isn't as smooth from a cold start. Even after software updates, my passengers still always complain about my car.

Diesels are known to be very reliable. Though there is the factor of the turbos that does add another item that could possible have break down in the long run. Don't forget that 2011 should be the facelift for the X5's and that would add turbo to current 3.0.

I wouldn't worry about reliability as much. With the 3.0, 4.8, 35d, I'm guessing it's pretty much the same across the board. BMW's aren't the most reliable cars. But they are great performance cars that are not poorly built either.

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2008 X5 4.8
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