It's not that it "needs" to be painted, just that bare CF doesn't really look good and seems a little tryhard. Think back to the early 2000's to every car in (insert generic street racer magazine here) that had a naked CF hood, then naked CF fenders and eventually whole front ends and doorskins... it's just a bit much and people have kind of realized that a car that's all one color looks a ton better. I think your best bet is to look at higher end vehicles that use composite material from the factory for inspiration. Think about Porsches, Audis, Ferraris, etc. and even though they're using carbon and kevlar fiber throughout their bodywork, only little accents here and there are left unpainted. As a whole, people tend to see a car with a nice paint job as a well built car, while street cars that are covered in shiny carbon fiber just look like a kid got ahold of a JCWhitney gift card.
Hope that helps clarify my position a bit. Post up some pics so we know what you're working with.
