roll on automotive acrylic enamel?

Im wondering if I could use the rustoleum method with some automotive enamel? I have a gallon of it that I bought on evilbay a few years ago and never used it.it came with hardener but I would use it without that.and just thin it way down like with the rusto.

I would like to know also because i have quite a bit of auto paint lift over myself and its all metallic. I would think that it would work fine untill the last color coat (especially if its metallic). I wouldn't sand that coat untill I put 2 coats of clear over it to protect the metallic from being sanded. If you don't have metallic then I don't see a problem. All that can happen is it won't work and then you can sand it off and redo it but I think you will be ok. I know when I do mine that is what I am going to use and that is how I am going to do it.
Metallic might be a problem but using the roller in several directions should ward off any streaking or tiger striping because you can see it and compensate with the roller.