We have gone to a 92-R52 this year and have been amazed with the performance. The machine is fully Hyperized with out the F2 bar. I've also got green stem beans this year. In 55-60 bushel beans we can run about 7-7.5 mph(gps) with a jd 653 row head and in 160-180 bushel corn(cob is really tough) we run about 6.5-7.3 mph with a 630 corn head. The only problem I have is we are getting some loss on the discharge end. I know you can use a F2 bar or a n5 reverse bar. What is working the best with out the loss of power or would the sweeps take care of this. Also we decided to put a 830 corn head on and could still run 5.5 mph what a monster. My neighbor running a 2388 said thats all he could do. Thanks for all of your help guys.