Welcome to GS! I wish they made a scangauge for your car. The feedback would make it into an MPG game for you.
Based on your car mods, I think you would be partial to those gizmos that allow you to modify the fuel map. Check out this car :
It has an Apex SAFC fuel controller.
I read this in your garage :
"-Dpfi>mpfi, obd0>obd1, vtec rywire conversion harness
Others can answer this, but does this mean that you are compatible with other aftermarket MPG monitors?
Love that Civic hatch. That's my favorite generation of Civic.