...I'll post it to Interlux and see what they say.
Not much help there:
"In the bilge area we would recommend using Bilgekote, but we have not tested Bilgekote, or any of our other topside paints to with stand an environment where they are subjected to high heat. There is a risk that in those situations the paint will blister and peel off."
Doesn't sound like they're ready to sign up to not cracking under pressure, I mean heat.
As far as sound isolation material, this is a Catalina 25 that does not really have a sealed engine compartment (there are opening panels in three directions and a hole aft, so I'd have to cover a bunch of small areas, removable panels, etc. Not ideal). I am thinking cosmetics and easier to clean next time (plus detect leaks, etc, etc)