Originally Posted by AM47
Just read the post, mine gets 11.8 L / 100km or 20 mpg, its all hwy driving, my 911 turbo gets 10.8 L / 100km all hwy driving, as a comparison my wifes X5M gets 15.3 L / 100km all in town driving.
I don't know what post you are referring to, but the OP has stated that he was getting 12.25mpg (and commented was almost half what I was getting), another posted 17.1 and yet another at 18.9 mpg. And others share the same mileage I am getting 20-23mpg. If you are getting 20mpg then that is better mileage than what you probably may be getting on a previous M5 model so in short, the turbo has increased the efficiency of the new M5 compared to previous models.