I've got a nice Wings West polyurethane kit on my car (been almost a year since installed from the previous owner) and it still looks new. Fiberglass isn't worth it unless you're building for show and aren't driving it, but even then, you could probably afford better. A polyurethane kit is going to cost a lot more though, sometimes about twice as much as fiberglass. And unless you want everyone to point and laugh at you, you're going to have to have it painted, too. Have someone that know's what they're doing install it. It'll add up.

Fiberglass isn't carbon fiber.