Now they are selling a "3 part" system, which includes a degreaser/cleaner for the first step.POR 15 requires a top coat of paint if exposed to sunlight.
It can do all of those things you mention it cannot do if not top coated
When it originally came out, it was sold as a single coat solution. Then the stuff started to chip, peel and disintegrate.
It then became a "two coat" solution as a result.
Its great stuff otherwise.