I have an opportunity to pickup about 500 acres of wheat to custom harvest and hopefully more in the future. I Been looking to get into this for awhile just finally have a good chance to get a start. I have been looking at both n7, n6 and r70, r60 and they are in my price range. Theres alot on what to look for on the N's but not alot on the early R's. So what are some of the problem areas i know they were air-cooled motors that everyone seems to stay away from but what were the main issues that i need to look for when buying one and also the any upgrades you would do right off the bat.