The knee caps were a major problem with paint rubbing off, just sand it down and problem solved. However don't sand the ring area of the knee caps, I think those are what keeps it stiff. The back piece that holds the wings should be sanded down a bit so it doesn't grind so much on the wings. Either than that, it held up very well during transformation, surprisingly very minor paint chipping.
forgot to mention, the "hip lights" rubs against the outer thigh, so sand that down a bit aswell.