I got 51.0 over 416 miles, including Glasgow rush hour followed by a run to Milton Keynes in a Mercedes C220 Sport Auto and thought that was pretty good.
The smart diesel is officially the most efficient production car with 85mpg and 88g/km. The new version gets 9% more power (54hp!)
Last edited by Iain Mac; Sep 7, 2009 at 10:00 PM.