Well CD I don't know about any performance kit for a 9600,but be sure to put the agitator strip on your shaker cross shaft above your seive and below the walker tray,otherwise the straw will give you a good blockup...
I will second the Kuchar kit as avery needed amodification to the JD9600. I farm in Ontario Canada and we combine heavy wheat and barley. WE installed the complete kit{ concaves,grate, risers and modified the preecleaner. This kit increased our traveling speed, smoothed out the slugging that we were having trouble with beforeand most importantly , the grain stayed in yhe machine. Give George a call. He will make you happy. del