Man, i drive basiclaly like a granny on the highway. However, they recently upped some speed limits here in TX. So, at 3 hours, cruise set at 80mph for 30 minutes, and 75mph for the other 2.5 hours, I average 24mpg. And thats with a stock '12 GT 5.0 Manual with 3:23s and 3k on the odometer.
I...