I really like the X6 too. It took me a while but whenever I see one on the road the just look amazing. Personally I would go with the 50i. But right now I am trying to make up my mind whether I keep my X5 and buy a used 06-07 M5 or just dump the X and get a X6.

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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