If the parts are the same color as their surroundings, then I would place and then paint. However, if the parts are a different color than their surroundings, such as seatbelts, I would paint and then place. However, superglue will possiblly fog over the painted parts. But you don't have to use superglue to attach photo etch parts. You can use a white glue, or my favorite, Testors cement for wood and metal. It works great and dries fast. It can get stringy though.