Polyester resin does not stick, long term, that well to steel, regardless of how well you prep the surface. Initially it feels like a great bond but repeated expansion cycles will break that bond. That's when the moisture thing starts. Also the cured resin bond is not very shock resistant, so all those vibrations from an actual driven car will cause you problems. First hand experience.

This book sounds great, I've been thinking the same thing. I already know how I would do the outside surface(being that I do a similar process on small scale items), its the inside support structure of the finished piece that I need help with.

Flip-up front end anyone?