I used normal paint for painting the Intake plastic bits in the engine bay. (Tried to colour code them to the Exterior paint colour)
I also used this as an excuse to try and find a paint colour that was close to the factory ford colour, so I used a few brands, etc etc.
Most of the paint is still 100%, but one part which I used no primer, and very cheap and nasty clear coat, deteriated.
Instead of a metallic gold, it now looks like a cheap beige colour.
So I assume from this that it would be OK, as long as the paint is primed correctly, and that you use a good quality clear coat to help protect it.