We upgraded from an M2 GlEANER. Talked to our AGCO dealer about next size up GlEANER. He told me the N series was complicated. R series got simplar, but the R5, R6, R7 were hybrids of the N series and the early DUETZE-AllIS R series. The earlier R50 used a hydraulic pump on the header to drive the reel(pre 89 1_2),'90 and newer used a two section pump driven directly by the engine. The final drives are (small) S-22 to S-31,(big) S-36, if I recall correctly. We have a '90 R50 6-30 corn 20ft bean head. I'm using a MICROTRAK GRAIN-TAK. I can run 1,000 to 1,150 bu_hr corn. If I run less it gets sloppy. When we use 2 trucks to dump-on-the-go,I can run 1,300 to 1,450 bu_hr. The single most important change I made was to add a TURBO BOOST GUAGE to monitor engine load. The other thing is to use corn bars for corn_soybeans.One important point I've seen from the messages is to keep the oil coolers clean. This year I used compressed air to blow backward. They "looked" clean but I was amazed at how much soybean dust came out.