How does using 4WD have anything to do with the car driving you?
One thing I do like about 4WD on dry pavement is that it lets me jump into traffic from a driveway more quickly with a heavier food without squealing the back tires. Other than that, I don't see any difference between the two...
I did a similar study in my 2008 4WD earlier this year. I ran alternate tanks in 2WD and 4WD for a total of about 8000 miles. I found a .25 mpg difference. My miles are almost entirely city streets or urban freeway where its impossible to maintain a steady speed like you could on an interstate...
What about the Nokian WRG2's? They're all-season but more winter capable than normal all-season tires. They don't have the aggressive AT look though.
Nokian WRG2 SUV
After reading this thread about 4LO not working, I tested mine today. It engaged smooth as silk on the first try. I did notice more gear noise (straight cut gear?) and a little rougher shifting from the tranny. Is that typical when in 4LO?