About the being overweight. Adding air bags does nothing for your capacities, it just effects your ride height and ride. As a former truck driver, I will tell you what will happen if you ever have an accident. If there is some question about fault, a good lawyer is going to try and prove your truck couldn't handle the weight. They will do everything they can to prove your drives were over loaded or you exceeded the specs of the truck. If you are a 100 pounds over, and they can compute that, there goes everything. I make sure my truck and trailer scale properly every year, even same truck and trailer. You don't want your life ruined by a lawsuit. As for the 4x4 or 4x2, I take that more as a personal choice. We have 4x4 but I see plenty of 4x2s. Good luck.