I get between 14 to 16 mpg depending on driving habit and top highway speed (around 75). I run 89 octane gas with Lucas fuel conditioner (6.2 engine hp is 450 with current mods and tune and yes, it will light up the rear tires). City driving varies according to traffic. Overall average is 14.6 currently. Mpg like tire wear (45k plus) is subjective to driving habits.
My 2011 has been getting 13-14 daily driving to work and back. Pretty much babying it around town. Highway I touched 16 on a trip. That was a pretty steady, mostly cruise control @ 80. Was a little surprised but didn't seem to be working too hard sailing along.
Gen 2 around town I'm averaging 14.6-15.4 mpg, when I get more highway miles in on the tank, I'm closer to 16.7-17.4 mpg depending upon how heavy I'm getting into the gas pedal. This is on 93 octane. I also haven't taken many longer road trips - majority of driving is around town/up the highway to a few towns over.
I just did a road trip from Central Texas to Michigan and averaged 70 to 77 mph for most of roads. I used regular for most of the fill-ups since I was burning through entire tanks and I mixed in some mid and premium on the way back. My average MPG never got better than 15.6 for the entirety of the trip. My GEN 1 was down around 12 or 13 if I recall on average.
Gen 2 on highway is 17-19 if you do 65-68. Bump it to 70 you go to the low 16’s. If you start running 75-80 your mid to low 15’s. 10 k miles this year with cruise control on the same 65mile round trip 6 days a week