With a 5.7L V8 GC, i get around 16L/100km in the city during rush hour. But surprisingly, it drops REALLY low on the highway. On the highway i hover around 8L/100km, which is insane because my Subaru WRX would get 7L/100km at best and this GC is a heck of a lot bigger and heavier. We haven't taken an official road trip with it yet though, so i'll be interested to see how far i can get on a single tank of fuel.