This! I exclusively roll in Sport mode and steadily get 15mpg...road trips see 15-17.That was from a roughly 1200 mile road trip, which included a day at the dunes and a lot of backroad driving and mostly highway otherise.
I average high 14s, low 15s normal which is about 60% highway and 40% city. I just drive it man. Use sport mode quite a bit and get on it quite a bit. Sounds dumb but the more I tried to get good fuel economy the worse it was. Lol... Just drive it and fill her up when shes thirsty.