They are all the same base sled. The dragon has a better shock package over the standard rmk and some extra lightweight items on it. The assualt has a stiffer and more adjustable shock package over the dragon and a few lightweight items but a little more heavy duty compared to the dragon. The standard rmk comes 144,155 or 163. The dragon comes with 155 or 163. and the assualt comes with a 146. The assualt has the competition track on it that is made for heavy set up snow. All the models come with a sway bar. All the motors will be the same throughout all the models.
Hope this clears it up a little for you