I was looking at this earlier for when my clutch goes. I try and get the least expensive option. They say the 3600 MAY require a hydraulic upgrade and with the 13" upgrade I was thinking that if you go to far that you run the risk of breaking the 1 1/4 shaft if you don't do the upgrade. And another thought is the difference between the 12 button 3250 and the 6 button 3600. I really don't know what this means but it's my .02.