Before I got my R50 last summer I seriously considered the PFP cylinder since my bars were about wore out. Talking to the guys at PFP they made it sound like it would perform all out of proportion to it's size and said they never had any complaints regarding shoe capacity once it was installed.
Thanks TBK. I was going to put in an airfoil chaffer as well to hopefully try to increase capacity a bit in the back. I should be doing this to a newer hydro unit, but the old M is in good shape and runs well.
OK, you've got a straight M so likely the airfoil chaffer is a good idea since you've got the "short shoe" compared to the later models. I'd guess the only limiting problem you might face would be your clean grain elevator in corn. If I'm thinking right your clean grain elevator is @5" wide, and the Corn+ and Corn/Soy specials are @7-1/4". I suppose that if that becomes an issue you might be able to speed up your clean grain elevator to move all that corn away faster!