I think it's a downward spiral. Simply put, once you have bigger axles then you try bigger tires, bigger obstacles, harder lines, generally more aggressive wheeling. All this combined will eventually put way more stress on the frame and body then it was ever designed for. One of the biggest things you can do to combat the effects, put in a real good roll cage and tie it in to the frame at all points. I'm talking from the tailgate to the front frame horns like an 8 point or more cage. This will keep, or at least prevent, the frame from twisting.