I totally forgot all about how elevation plays a roll in mpg.

Want to improve gas mileage? Turn off AC.

I'm not sure I buy that, at least not for me.

If you check my Owner's Journal first post I track all my fuel purchases and MPG there going back to May, 2012. Living in Georgia, I pretty much run my AC from May through September, and either don't use it, or use heat from October through April. This is my average MPG by month between 5/2012 to date:

Average of MPG
Jan 32.40
Feb 32.42
Mar 32.28
Apr 33.12
May 32.74
Jun 32.72
Jul 32.91
Aug 32.75
Sep 32.72
Oct 33.34
Nov 32.46
Dec 32.39
Overall Average: 32.70

With the exception of April and October, not a lot of variation there. In fact I seem to get better mileage in the meat of the summer (July/August) than winter (Jan/Feb)

Can't really explain the April/October anomaly other than those are the months I'm most likely to not be using either heat or AC. I also tend to take more solo highway trips, which means the FR-S, during those months.

i don't drive like a grandpa, but i also see a lot of back roads cruising at 55-65 so i get around 30 all day with my wide ass tires.

if i was on the primacy tires i'd be around 32-34

This pretty much describes me. My average speed is probably well over 40MPH over 68,000miles at 32MPG. First 60,000 miles were on Primacy tires, the remainder on Bridgestone Ecopia all-seasons. No difference in mileage between the tires, but a huge difference in grip and ride.