I'm in, with three 70+ mpg tanks from the winter beater Metro this spring/summer, the last 2 being consecutive records for the car!
The Metro has all the same mods as the Firefly, minus the rear wheel skirts and the taller-geared transmission. (I actually have an extra Swift gearbox to put in, but I haven't gotten around to it.) The Firefly could deliver slightly better than 80 MPG US in similar weather conditions & routes. Typically that means cruising on scenic/back roads at or near the 80 km/h limit (50 mph).
Unfortunately/Fortunately for me, I have parked the Metro! I'm now driving
the MPGiata until probably early November. In that car, I have to drive very carefully to eke 50 MPG out of it. No more hat photos for me!