I am looking at a Zetor 8540 with 2000 hours and a Zetor 6340 with 300 hours. I will use the tractor for plowing, small operation, running the 9' discbine and 4x5 round baler. Read the pto in 6340 had some issues. I can't figure out the differences. Same year of manufacture and 6340 is 77 hp and 8540 is 80 hp, at engine. I would like to get the 6340 as it is local. Both cab tractors. Can someone explain which tractor would be better and why?