mpg....I have two sets of 19" tires one the summer onlys. I've seen 26.5 (math) once on all hwy around 75 mph. Every time I see someone getting 27/28 I feel like an oaf. B4 you switch try a distance of cruising keeping it in 5th (or 4th) to simulate the higher rpms you will be turning on the hwy. If you take a trip you might find that 1/2hr of 2600 rpm will drive you bonkers and it's an easy/cheap test beforehand.
I'll try that today.
Steeda tune, Steeda ultimate induction cold air intake, BBK tuned length shorty headers, Idatalink maestro.