Thermal paste to put between the heat sink and motor is a great idea, to fill in any tiny air gaps that might be there. Air gaps make the heat sink work like a blanket and hold the heat in.
As for diff. weights, I have no idea.. mine are all stock. And, New Eras wheelie bar will cure your standing back flip issues. I can be sitting still, hammer full throttle and just go.. I recommend getting one.
