I regularly do 70-80 mph on the highway with the occassional >100 runs for the punks in their rice burners or the stiff in their Bimmer, but the key is using cruise control. I pull regularly around 340-360 miles to the tank. So, 24 mpg with a heavy foot really isn't that bad at all. Plus, keeping up with the scheduled maintenance helps too. No aftermarket mods (yet) on the performance side, but I'm working on it. I haven't been in town long enough to get any joy in doing so yet.