I have a 585 that is due for cylinder bars and rotor wear bars.  It has been suggested to consider a Sunnybrook cylinder and impeller.  Precision Machining has also been discussed as an aftermarket impeller option.  I'm curious anyone's experience and opinion on these?

As background we are running white food grade corn, seed beans, and non gmo beans through this machine.  While I like the combine it can be hard on grain quality in some conditions.  It also struggles in green stem beans.  

All input appreciated!
TIA