Nothing unfortunate about being stock, I have no doubt most owners think the car runs great the way it is. People who peruse forums are already inclined to mod, there must be tens of thousands of SHO owners who never thought of modding their cars.
Back to mpg, I average 21 mpg city/highway. That's 4 mpg better than the '13 Coyote Stang I had, which is fine by me!