350 4x4. What engine does that 08 have. Its not the 6.4 is it? I have heard of some pretty poor mileage with those. That truck is almost 7 years old. I am not surprised it can be bought for 25k. As another poster mentioned a world of difference in the last 4 years as to payload and many other things. I had a 2008 duramax 2500 hundred. It was a great truck but my 2011 3500 has about twice the payload and way way beefier all around. It handles my 5th wheel a lot better. Also I would not even be able to have the TC I do with 2008 2500. JMHO