Can any one tell me why Carbon pre preg material is used for the production of Molds for Carbon Chassis. I was reading an artical in racecar eng and it showed the Force hillclimbe chassis being made form Carbon fiber tooling pre preg. What would be wrong with good old glass fiber? Also lola make most of there body molds from carbon aswell. I understand the reason for epoxy resin being used over Polyester it shrinks less and is stronger. But what would be wrong with using a Vinylester high temp zero shrink resin with glass fiber?