I've got the brochure in my hand now I'll read it to you word for word. "Turn your John Deere into a crop residue manager. Achive a finer cut, wider spread, and superior performance with a complete MAV residue manager or a MAV rotor upgrade to the factory chopper. Improve the MAV rotor upgrade even more with these options: 1. Optimized 12 vane tailboard for the widest speading capabilities up to 45 feet. 2. tight knife bar kit (1 inch counterknife spacing) for the finest posssible cut." For, I think around $2300 to $2600 you can just get the MAV rotor and drive pullies. I believe JDs are the only ones where you can simply throw a MAV rotor into the factory chopper. We're thinking of doing this to our 9600.