Bigger shoe hangers/bushings which might translate into a bigger shoe, rotor looked longer, and had a rethresher.  What I am getting at is inside, the design is the same as the smaller ones but may be bigger.  Just from my 10 min observation.  For a year or so I read and hear on the internet how the new combine might have 2 rotors or a bi rotor.  To me it looked like a 9770 on steriods, nothing special.  The operator told me they had over 30 protos out so not all might have been the same.