[EPIQTodd]

For a spoiler, fiberglass is just fine. No advantage for polyresin on that one.

Regarding carbon fiber and composites, I wholly disagree that it is a 'low tech' process - if done poorly, it is, but done correctly, it is VERY high tech, and difficult to do. Those who do the half-ass method of just using resin and drying in the open air are just making fiberglass with carbon fiber sheets. True carbon fiber and composites must be cured in a heated vacuum, and that is what makes good carbon fiber what it is.