Composites is my field of study/work. A good wrapping orientation can give carbon/epoxy a tremendous strength-to-weight gains over a metal driveshaft. The downside is impact resistance. Regardless of what ANYONE tells you, a carbon fiber driveshaft will have inferior resistance to anything that gets kicked up from the road (stones, etc) as compared to a metal shaft. A good compromise is a metal matrix composite (MMC) driveshaft. These are most often made from aluminum, and some kind of reinforcement is added to strenghten the material in the direction where the highest stresses occur. I don't know what your plans are for the car, but I would skip a carbon driveshaft if it's driven often on the street.
