Looking at buying a 3500 dually with a 5.9 Cummins in it. This would be my first diesel truck. Main use would be hotshot rig local and regional only. What do I need to look for when buying used. It has 161k miles on it and appears to have been kept well. It's loud and the salesman says it has straight pipes. I'm concerned about passing TN State emissions inspection. Any advice is appreciated.