I get about 18-20mpg going back and forth to work. Went on a few road trips and got between 26-27mpg.
The first few weeks I had the car I got about 12-13mpg -LOL!
I think I set the mileage benchmark that no one will be able to beat.
Last week, commuting, almost all highway, my 2011 GT 5.0 got 31.0 MPG on a tank. I have a fuel mileage friendly commute, and a fairly calm driving style (regardless of what I drive), but I was still amazed I was able to break 30 with a 400+ horsepower engine, particularly with the PZeros.
Right now I'm getting a shade over 22 in my '06GT with 7700 miles. It's up from about 20 when I got the car with 6400 miles on it.
She was a weekend car for some folks that traded her in. Mix of highway and city