POR15 Rust Preventative Paint - Do I need the Topcoat too?

[TroubledSoul]

Hi folks,

I'll soon be painting the front and rear subframes of my E36 and the associated rear suspension arms with POR15 rust preventative paint. Do people use this on its own or would it be advisable to paint at least a layer of their top coat paint over it once cured?

I've not used it before but want to get it ordered today ideally so any help is much appreciated.

[TroubledSoul]

Nevermind, I realised I actually asked about this ages ago and didn't get around to the job then. At the time it sounded like the RustBuster Epoxy mastic with a bit of POR15 top coat over it was the better bet.