i think it is the placement of the exhaust pipe actually... the pipe itself moves in its mounts and can slide closer to the plastic from vibration if it is not tightned properly

 

Mine melted at 500miles and again at 600miles. Polaris replaced my plastic out of warranty TWICE. Kudos to Polaris for replacing my plastic. I just drive it with the melted plastic...you cant see it, its under the seat. Took my third set of plastic and stored it in the basement. That way if I sell it or trade it in someday I will replace it then, no sence in doing it now cause it will happen again. I like Polaris, I love the way my sp700 rides and performs but I will not buy another one until they change body style.