Carbon is standard on the bottoms of the Gen3 rudder blades. Kevlar is the toughest in this type of application (I use it when building a composite part intended to skid along grass/concrete etc.). Trouble is it's the worst to work with and paint doesn't bond well to it. By worst to work with, I mean you need to modify scissors to cut it, and once it's in a layup its an absolute dick to finish cut or finish sand. Will require a hand sander and lots and lots of 60 grit sand paper to get to final shape. But it'll hold up better to repeated groundings, if it doesn't de-bond from the base layers.

http://www.fibreglast.com/product/Kevlar_Pulp_544/Fillers