The HCH gets at least 50 mpg at 70 miles per hour, though not at 75 miles per hour, but keep in mind that figure was only for a level stretch of road. Actual highway driving often involves going up hills which costs more than you gain going down, and it often involves short spurts of acceleration due to traffic, where you slow down maybe 5 miles per hour and then speed back up, repeatedly. Plus that's not even counting accelerating onto the highway in the first place.

Well I'll definitely post detailed results when I get the car, but it could be as long as two more months (though hopefully less). I'm trying to hold out for the exact color I want, Barcelona Red.