I now own an '01 Chevy 3500 Duramax. 4x4, extended cab, dualie, fully loaded, with 60K miles on it. It used to belong to my dad, but he decided to get an '06, and sold me the '01. Ok, the maintenance has been kept up on it, but it is in desperate need of tires. It came equipped with Wrangler AT/S's, and they seemed to last a long time, but a lot of the mileage on the truck was interstate. I seriously doubt they'd be very good up here in the mountains, where I will be for the next few years. What can you suggest that has worked well for you? I'd like to go up a size or two over stock since the factory size looks goofy on a truck that large. Power-wise, I'm not complaining, but it could use a small boost. I don't know if I want to get into programmers or chips, but I would like to upgrade the exhaust. It could also use a better braking system, like an exhaust brake or something, as the tow/haul mode on the truck doesn't do much at all. I don't know much of anything at all about diesels. What can you tell the rookie?