do i have to use hobby spray paint

[Bondonutz]

As with Lincpimp, I am a Autobody repair tech and use urethane BaseCoat for all my bodies and it holds up extremely well. Bulldog is the cats meow for superior adhesion for any rc paint and definitely a worthy investment. I don't use urethane clear to back the color though, I let the BC flash off well and dust rubberized undercoating over the paint. The undercoating is the shizzle for durability ! The clear will flake off in a hard crash if to many coats are applied, the Undercoating stays flexible regardless and offers chip protection.
If you use spray bomb paint thats not specifically designed for the poly bodies eventually it will fail. Your best bet for non RC body paint is first a coat of Bulldog and few light coats of a "laquer based" spray bomb. Never use Enamel, It will flake off on the first crash.