Need engine mods or tune better MPG

[GasSavers_gunrunner]

Hi All.
I have a Subera Legacy L wagon AWD 2.2 engine Auto trans. I am new to Hyper Milling.
I originally got 23 city and 28 hwy. After some mods and driving changes I get 25 city/31 hwy.

I need some help on making engine mods or tuneing. For FE

Thanks for any help you can give me,
If you would allso name the best car for Hypermillling Gas only.

Thanks,
Gunrunner: