I have the 2012 model with the 31 kasi with the HyperDrive hydraulic system - 60in xv4 deck - flex forks. Love it - ride is great in most cases. I cut some lg vacant property's that beat me up somewhat. With my weight I bottom out the seat at times. My local dealer had a 104 SZ with the Grammar seat on it and I seen that it was rated for 370 lbs, [I] tried it out and loved it. It is supposed to be delivered today. I really didn't see the reason for all the speed the Z has with me not being able to use it thus the new heaver rated seat.