mpg
On longer trips or in somewhat aggressive driving (meaning keeping it under 4000 RPMs) the 320 engine is a stellar engine in both performance and efficiency. Put it this way, if I were to take a long drive (say two hours approximately) on the highway, an E320 would probably beat the efficiency of a C230 if I were to put the cruise control at say 70 MPH (speed limit on I5 is 70 MPH).
The 320 engine is simply a stellar engine, more than enough power for daily use and excellent efficiency. I've never had to complain about high gas prices.
In my experience, the E320 averages about 22-23 MPG and the C230 averages around 25-26 MPG. However, the E320 is driven in more traffic and driven more aggressively than the C230.
All of these measurements are taken inbetween fill ups. The MPG calculator in the trip computer is not very accurate on these vehicles at all, beware.


