There are many different types of plastic, gloss hips that will not require paint, Matt hips that will. Also gloss abs that will not need paint and Matt abs that will.
I'm working on an abs suit that will need paint. It's very easy to work with and easy to cut. I've also built 3 abs suits that did not need paint. Again very easy to work with. And I've built suits from hips, that again were easy to trim and needed paint.
I would do more research and look at what level of work you want to put it to it.