I'm in, lets help figure out how to get THE BEST MPG out of the FiST and make it an even better economy performance car rather than the other way around. Why not, it's a challenge, a different one then normal performance mods but that could make it more interesting. I'm sure hypermilers know all tricks to eek out the last little MPG maybe they can chime in (e.g. dimple the body for less drag.) My first thoughts are most performance mods are going to help. I think running higher octane, with a low boost economy tune is probably a good start. Even adding a bigger turbo will, help. The more cold air you can get in the engine the better.
The next thing would be put lightweight wheels and taller narrow tires on it and fill them up to max pressure, no traction, but who cares when you have little to no power lost to friction. I think the RMM upgrade would help with the lower gear shifts making them more controllable, and again less power lost to the engine moving around. Maybe the big mouth, and high flow drop-in intake filters would help with more air. Also weight reduction, pull all the weight out you can, replace the spare tire with repair plugs and a small compressor, pull out the back seats, carbon fiber hood, etc. I recall a thread were someone with a bigger turbo was talking about how much better their MPG was, maybe I can dig that up. Any other ideas?