I've owned mine for 2 months now. Love it.

06, 5.9, Megacab, 4x4. previous owner lifted the front end via leveling kit, added 12.5x35" tires.

I bought it with 87k miles, right at $30k.

This thing is a tank. with these tires, it rolls right through anything and keeps on going. Mileage seems to be around 16, although the lie-o-meter says 19.5 at times. I did add a smarty jr POD within 2 weeks of owning it because I got a good deal on it. I'm leaving it on level 2 for now, because the guys on the cummins forums say that with a bone stock auto trans, level 2 is safe, level 3 has potential to break the trans. On level 2, it picked up a tad on mileage as long as you keep the RPM below 1800, even when accelerating. mash the go-pedal, and it'll spit out a small cloud of smoke then clear up once the turbo spools, and it pulls smooth and strong all the way to 80 (and would keep on pulling, but I have no need to take a 7,000 lb truck faster than 80)