I am looking at a 1680 with 3800 hours to replace my two L2's. It is real clean with a lot of updates. What should I pay attention to when looking this machine over? The sheet metal is straight, auger flighting good, Cummins engine overhauled due to a bad liner, etc. Overall it looks really good. Cut mostly wheat, beans, and a little corn. Almost 4000 hours would be a lot on a conventional machine, but what what about on a rotary? Any advice appreciated.