Love the guys who claim 20+ in a modded V6 truck.
The absolute most I was ever able to get was 24.1 MPG, this was in a bone stock, well maintained, 4 cylinder, 5 speed, 2WD, rolling on 235's (28"), with 3.73 gears and absolutely no extra wind resistance (not even a factory rack), 95% highway at 55MPH, driving like a grandma.
That is literally the perfect set-up for maximum MPG's, and I did it through multiple full tanks, I think the most I got out of one tank was like 390-something miles before filling up.
Now, with all my mods I'm basically the worst case scenario when it comes to MPG's, Suspension and body lifts, 35" Tires, 4.88 Gears, lots of added weight and wind resistance (Plate bumper, multiple roof rack bits, roof mounted lightbar), and somewhat underpowered (more throttle, more of the time) and I'm lucky to get 15 MPG.
There is no point in lying about your MPG's anyway, telling people you get 25 MPG isn't saving you any money.