Last week I finally found the 2013 GLK 250, with under 20,000 miles, one previous owner, that I have been search to find. Wonderful auto. On the way home from Portland, OR we made an honest 38.2 MPG. My wife drove part of the way (we had two cars) - and she drove much faster (85++) than I did (I am used to my 300GD non turbo diesel..). I believe that had I driven the whole distance at 60-70 MPH, I would have come closer to the 40 MPG figure.