if the panels are new theres no need for primer, water based paints are no better than any thing else,and as to what paint is best all painters have there own prefered paints,as long as its a decent 2pack paint and the bloke doeing its good all should be well
we'd charge about £350 if you brought just the panels but were in the midlands
Avoid places doing it to cheap,because if the moneys not there,the blokes heart aint gonna be in the job,he'll just rush it and then nobodys happy