X3 35i M Sport fuel economy

I'm considering an X3 35i M Sport for my daily driver. My Edge Sport is roomy for the bird dogs, but is thirsty, barely cracking 20 mpg@ a constant 70. My E63 Wagon was swift, comfortable, flew under the radar, but REALlY thirsty (it made my Ford GT look economical). The X3 35i with M Sport seems like an ideal compromise. My question is, what kind of mileage can one expect @ highway speeds with the cruise on? My '06 M3 competition was actually pretty economical if I kept from burying the tach (frequently 25-27mpg@70-75 mph), so I was wondering what owners of X3s with the bigger 6 could expect?
Thanks in advance.

I get 28 on the highway (with cruise set to 75-78) and 20.5 in the city.

Originally Posted by Want the Thrill

I get 28 on the highway (with cruise set to 75-78) and 20.5 in the city.

oh dang thats what I am getting from my 2013 28i.

I could live with high 20s. It is the mid-hi teens stuff that's getting old.

I haven't seen anyone with a 35i report mid to high teens on the highway so you should be good to go!

I have an '11 35i, with the '11 Sport package (transmission, seats, etc.) and DHP, but not the M-sport cosmetic components. When doing all highway driving, below 65MPH, I've gotten as high as 29 mpg. Above 70-75MPH the mileage falls back down around 25 mpg. Driving in Sport Mode hurts mileage (8th gear is locked out unless you manually shift to it, just a flick of the paddles or shifter), and using Cruise Control helps mileage. Properly inflated tires will also help mileage.