Internal engine coatings?

Thanks for digging this back up guys! The reason I asked is I was reading some of David Vizards writing and it seems like he is a HUGE believer in coatings, but it also seems sometimes for product placement...

Leanna, do you think the thermal coatings would even show an improvement on hyper pistons? Are bake-em-yerself coatings as any a professional would have? (with proper application of course)

I'm all for anything that'll protect my engine, even a little, by preventing detonation or such, but I'm a little weary of products being a scam.