The car did awesome....
left at 5am Tx time. got home 12:15 that night.
in short basically did 90mph most of the way back home.
at 90... RPM's were at 4100. and I still got 24MPG. this is with crazy cross winds from Arizona thru New Mexico.
I did do one tank at no more than 80MPH and I got 26PMG.
Toward the end I was really getting tired and was going mostly above 90 and got 21MPG

The BEST THING about the whole trip is my CEL light went off and is still off.
the code was a weird one. something about the car not recognizing when the the cars is turned off. hahahahaha. I'm sure it'll come back on the day before I need t get it inspected. lol

 

I did 3600 miles in 5 days in my 08 5spd, slept in the back, probably averaged same pace as you with air on constant, with similar mileage. 117 degrees in AZ/NM!