Well...there's at least one somewhat useful paragraph of Mirage review buried in that Sudbury history lesson...
I can't argue with that. You aren't going to get great fuel mileage driving a Mirage at 75mph (120kmh) in the middle of winter. I could have told them that....in our testing we found it to be most efficient around 90 to 105 km/h. The Mirage has enough power to cruise as fast as you please on public highway, but pushing the needle past 115 km/h will cause economy to suffer simply because that little three-cylinder is working! With an average speed of around 120 km/h, our test economy was 6.3 L/100km.
Still impressive, but not that much better than a 2021 Honda Civic, which would return 6.5 L/100 km on paper and could likely do so at higher speeds than the Mitsu. The Mirage is best suited for city life, but it can be pushed into road-trip duty in a pinch.