Andy is right.
Pick your poison.
The repair is doable if you have some skills. Mainly body work skills. The fiberglass is somewhat easy, with a stiff backer on the inside you can fill and patch the outside. But then you have to blend the build up so you don't see it. If you repair the inside, it makes the blending/filling on the exterior easier. But, the fairing only has so much room on the inside so be careful there too. And yes, you will need to buy all the fiberglass stuff too. Cloth, epoxy, micro, cups, brushes, mixing sticks, peel ply, etc.
Replacement entails cutting fiberglass and installing the hinges at the trailing edge. Going this way eliminates the need for actual fiberglass work and is the easiest and best if you have the skill set.
If you can, I would suggest recruiting some experienced help!
RV-6 0-360 C/S 1100+TT
James cowl/plenum, induction, -8VS and Rudder.
Louisa, Virginia KLKU