Calibration, Calibration, Calibration ! ! !
I can't say it enough. I am traveling on business and I am driving an '08 Malibu "Classic". (It's an '08, but not the new car)
This thing has a 4 cylinder with a 4 speed auto trans and it is BETTER on fuel than my '07 Focus!!! (Mailbu is better by atleast 4MPG) But it is geared so that it only spins 2400 RPM @ 75 MPH. My Focus spins close to 3100 RPM at the same speed. And it is NOT a slug! If you put it to the floor this thing scoots. I would say better driveability than the Focus as well.
I have had (2) different Malibu rentals and I can EASILY get 38 MPG out if them driving 75 MPH. The Fusions I have driven are LUCKY if they see 28 MPG.
About a year and a half ago I test drove a 500 with a 6-speed auto. I got out of thinking who ever calibrated it and chose the gearing was clueless. It spun way too many RPM.
So, all the gears in the world aren't worth a handful of spit if they are not properly calibrated.