Just an update. I did take that trip down to South Carolina. I drove 1,773.3 miles round trip, used a total of 49.18 gallons of gas. Going down, running 75mph on cruise, in ECO, mileage was just over 36 miles to the gallon. My best mileage was coming back, again, in ECO, cruise was set at 70mph, mileage went up to just over 38mpg. Average for the whole trip, 36.05mpg! I traded in a 2015 FIAT 500 that got roughly the same mileage, but the KIA is a much bigger car and to get that kind of mileage, I'm impressed. Plus, the KIA is much more comfortable on a long trip. Think I'll keep it a whileI recently purchased a used 2016 Optima w/2.4L. So far, car gives me between 30 - 35 mpg around town. That's in drive mode. (I tell people I drive for economy lol) Was curious how the ECO mode would work. Took a road trip, filled the tank 1st. Was able to get on the highway, switched to Eco, set the cruise control at 65mph. I did 204 miles round trip, gassed up back at the same filling station. Took 4.75 gallons. Did the math, eyes got a little bigger, just under 43mpg! I'll be retesting this in the very near future as I'm driving to Myrtle Beach in about 10 days. Will let you know my results if you like.