I wish I could afford the duramax, this is the 6.0. As far as tires, I looked for 2 months and I ended up going with toyo at extreams in 285/75/18. They have a pretty aggressive tread but just a bit less then the mt's. Figured they would b perfect for on and off road. I too drive around on the farm abit, just got them on tho and haven't taken them off road yet. It is also an E rated tire and rated for 65,000 miles but we shall c about that.