B-Run, you are certainly correct about the chip/warranty issue. I used the tuner so I could re-tune it when ever I needed to swing by the dealer for anything (which was only one time I can remember). that, currently, is not traceable in the truck's computer. I paid about 35k for the truck and drove it for a couple years and sold it for 32,500. Considering the tax benefits of writing off mileage, I came out just fine. Haven't heard of the 50k trucks, but when the duramax first came out, dealers might have been asking a huge premium for the first few. I also put a canopy on it which instantly upped the mileage by 1-2 per gallon. Added a k&N filter which helped a bit to. I ran the Delo oil, I think if I had gone to the Mobile 1, it probably would've added more mpg's. I think 24 is doable with a few mods.

Also, the Powerstrokes aren't broken in until they hit about 25,000 miles. Up until then, you haven't seen your best mileage yet.