[gtpvette]

I would think building a one-time use male mold would be easiest. Use fiberboard for the large flat section, you'd need a form to attach it to keep the shape. I'd use shaped foam for the curved sections. Cover everything in AC duct tape then lay on a few layers of mat and cloth. Try to keep the layers of glass equal as it's easier that way. Once dried pull out male mold,, will probably get destroyed in process. At that point smooth glass as best you can with 36 grit, then lay bondo to perfect shape. Prime then either paint or possibly overlay with CF.

The hood scoop and manifold cover were both made this way.