we probably have differing fuel maps over here.... different tunes for the crap fuel we use...... my V8 gets on average highway driving around 10 litres per 100 kilometres...... doing both light traffic, and highway, with me driving it sometimes during the week... and i ain't gentle on the throttle, it will average about 12 litres per 100 km....... straight traffic is about 14-16/100
now because i can't be bothered to convert those figures, 3.7 litres per U.S gallon.... and 1.6 kilometres per mile
We run 98 octane fuel here..... but i know your RON ratings are different. Our standard unleaded is 91 RON
Over all, i think they get excellent mileage for what they are!! if you want to have miserly consumption, buy a Hyundai