On highways at 110 kmph (no speeding and no braking!) my X5 diesel (2006, auto) can do with 8 liter. But in town, as we know them in Belgium, it is not hard to see 14 liter appear on the screen.
IMO the weight is the ennemy next to the automatic gearbox and the sportpackage with the huge 285 tires. I can image a manual with 235 tires being more economical.

But then again, no complaints cause those figures are to be expected with that kind of vehicle. Glad not driving a 4.8is when it's time to fill up with fuel.