I rode my 12 back to back when we tested the 13 when it first came out. I swapped back and forth 6 times before I could say there was MAYBE an ever so slight difference. That 21% is minimal. My 12 actually beat the 13 in a uphill race twice and my buddy and I swapped sleds. If you didn't know which one was belt and which one was the chain you wouldn't know by riding them. The 3 inch with the chain case is going to be awesome and will be geared right out of the gate. My bet on the 2.6 is it is still geared too high like polaris has always been. From a performance standpoint the 3 wins in the mountains. It works better for 80% of the riding we do. The only place it doesn't is the trail. Even on the bad days we always find decent snow in the trees. I think poo big push of the 2.6 was to downplay doo T3.