[DonC]

Wow, tough room.
13.8 is respectable with your gearing. I'm running with a 3.07 rear .82 fifth and 17" wheels and see around 15 with steady highway speeds. Mileage really goes up when I get over to Colorado and run at 5 to 10,000 ft.
Longest one day drive Portland to San Francisco (about 650 miles). Left foot never fell asleep but on the plus side the cockpit and seats have enough room to move around a little. Wouldn't want to try it without the dead foot though.
DonC