I have an 05x OR 6 Speed 4x4 bought in late Mar '05.

Lifetime Mileage: 47,522
Lifetime Gallons: 2,634.3
Lifetime MPG: 18.04
Lifetime High MPG: 20.04
Lifetime Low MPG: 16.45 (first tank)
MPG pre K&N Drop-In (12,642 miles): 17.55
MPG post K&N Drop-in and Mobil 1 Synthetic: 18.22
Low MPG post K&N Drop-in and Mobil 1: 17.37

Mostly mixed driving, and AC consistently on here in South Florida. And since its S Florida often bumper to bumper traffic, and when there is none usually cruise on highway 70-80mph.