EASTWOOD that offer car restoration supplies has some really good interior paints for 1:1 cars that are really plastic friendly and work great even without primer as I've been using this stuff for a few years now and likin' it very much. The brand name is SEM and is offered in a variety of colors. I have a couple cans and so does a friend of mine, so we often share when the need arises and that way have more colors available between us.