On things like paint, results on what's good is one thing that has changed thru the years. And an area where your experience might vary widely from mine. Between formulation changes, the EPA, your prep vs mine, and too many other things to count, your results might not match somebody else's from 10 years ago.
I'll say that as much POR 15 as I have used over the years and most of it has done what they claim and then some, I had extremely poor results with their engine paint.
I have 2 that I am gonna try in the future.
One is Bill Hirsch, I've heard good things about but I have never seen that anywhere else besides mail order.
The other one is Eastwood, there's a location close enough to go there and pick some up.
Rattle cans such as dupli color also aren't what they used to be. There's 1 other brand of rattle can engine enamel whose name I draw a blank to at the moment, and they're about the same as dupli color the last time I used them as well. Not what they used to be.