Are the roush quarter panel window louvers plastic? If I buy them and get them painted wouldn't the paint start to peel off and the item itself warp slightly?

 

I believe they are made from ABS plastic so they are very flexible. Before you apply the paint you top coat the part with a flex primer. It gives the paint something to stick to and can flex without the paint peeling. I did mine myself. 2 coats of "Bull Dog" flex paint, then 3 coats of paint and 3 coats of clear.