I've never had a single issue with my stug being underpowered stock. Broke a few track links. My main deal is the all the debri that gets into the palstic tracks and jams up the sprocket, then the plastic clutches always give. I figure if it had metal tracks maybe it wouldnt be so peppy, but the stug has such a narrow track to begin and pretty short length I'd thik kit wasnt needed. The 3:1 is going to slow the tank down isnt it?