I didn't know that epoxy paint was used in the auto industry, but epoxy is fuelproof, so that shouldn't be a problem, enamels and urethanes should be mixed with their respective catalysts, hardeners, that makes them probably one of the best choices for painting, there are some synthetic enamels (Nason) that use a catalyst, which are very inexpensive in comparison to the other two, they are used in the auto industry on cheap paint jobs, but for model use, they are fine, although, they don't recommend to spray clear after the paint has cured (usually 24 hours).
But any of these finishes, in my personal opinion are the best for model use, long lasting, fuelproof and shine forever.