our c230k estate does sround 30mpg on a longish run, getting around 300miles to the tank (small tank is a bit annoying) best i have seen is around 35mpg on a run from wassennar down to Roermond at 120miles we stuck to 70-80mph but we were fully loaded with roof box, we also find it quite good around town, the torquey motor allowing the box to get into 5th at 30mph. i'd imagine if you drive very hard you will see figures dropping to the teens, but to be honest you really don't need to thrash this motor to see a lot of cars dissappearing in the distance behind you, just let it haul you along on the torque, not forgetting the C230k is a 145mph car, with reasonable 0-60 and excellent midrange performance, and if i compare with the 406 pug we had, i think it is quite economical, show me a car that has the same performance with the same fuel economy!