Painting the outside is bad. One hit and the paint will come right off. clear bodies were meant to be painted on inside. Styrene bodies were meant to be painted on outside.
You can clan up the Testors paint with lacquer paint thinner and a Q-tip and gently remove the paint from the lexan. It will cloud up some but use a Dremel tool and a buffing wheel with buffing compound and buff the area clear again. It dose work but slow. It won't look 1`00% new but it will be...