Originally Posted by wch X5

I've had a '07 4.8 and now a '10 3.5d. My experience is that the gas mileage difference is significant even in the city. I was getting around 12 mpg in the 4.8 and now about 17.5 in a very green diesel. Highway is similarly different.

As for hp vs. torque, I think they both have excellent pick-up but the 3.5d feels lighter on its feet. The 4.8 was definitely smoother and at speed on the highway felt stronger (going from 55 to 70 mph for example).

I'm pretty happy with the diesel. I have had the occasional issue with certain pumps not working well on fill-ups but like the upgraded electronics on the '10.