Paint weighs next to nothing. It's not gonna add weight. Otherwise all military aircraft would be left unpainted, and weight is a much greater issue there.
IMO, I don't think it looks cool if it mismatches...especially if it's on a white car. If it did look cool, the Blue Angels would leave all their composite skins unpainted. After all, it would save time and money. If I were gonna show off a carbon fiber hood, I'd lift up the hood and show the inside as being CF. Or, I'd leave a couple of small circles unpainted so that you'd know. But why would you want to show it off? If I got a bigger turbo, I wouldn't get transparent lexan fenders and hood so people could see the turbo! They could "see" the turbo by the performance! The same goes with a CF part...you could "see" it by performance.
I am well aware of imperfections of CF parts. However, there are only so many imperfections (size and number) that are allowed. If done correctly, CF parts come out fairly perfect. I know that paint does in fact adhere to CF parts, but only in the aerospace field. I'm not sure if automotive paints may have a problem. My guess is a coat of primer and a couple of coats of paint would do the trick. Maybe it's just me, but an unpainted CF part gives a car an unfinished look, unless it happens to be on a black car.
Oh well, to each his own. It's definitely not my style :wink: