You can't just use a primer, it will hold in water and rust the under panel. Etching primer is to stop that, but needs a top coat to protect it. You need a satin color; witch will come out like a flat primer color. Single stage paint is all you will need. You don't have to use clear with SS.

But like I said, this has been done like 1,000,000 times.........don't do it. First it will hold in dirt. Like if you touch it with dirty fingers, it will stain it. It' also getting old.

What color is the car now?