I can tell you that if you are a current 540 driver, you will be disappointed with the performance of the 3.0. When I am drive on the free way for a couple of hours I will get 21-24 mpg. From everybody here on the board is sounds like the 4.4 get very similar gas milage, maybe just a little less. So you may want to drive both and then decide. I have an 01 and its nice, but I think you may want to go with a Facelifted model because they just look newer. I am still on the original motor, transmission, drive line, front and rear diff, transfercase. Needless to say I am pleased. But I would have bought a 4.4 4.6 or 4.8 knowing what I know now.

Happy hunting,

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2010 X5M /// R63 AMG...Wifey's 540HP Family Hualer

2001 X5 3.0i Sport 335,448 miles & counting...
SMG M3 Steering wheel
E46 Stainless Racing Headers
4.6is Exhaust
Turner Pulleys
Afe Intake
Brembo drilled rotors
PowerFlex Bushings
Hualingan
30mm H&R Spacers rear
20mm H&R Spacers front
Bavarian Autosport High-Performance Coils
Active Autowerke's Performance Software