That is super impressive!
I have the smaller 50-size 4st version of the P-56 and just love how easy it is to fly. So when I saw the ad for the 50cc version, I figured this was the model to put behind my $1,200 UMS 770. I just couldn't imagine putting an unflown engine (of a kind I'm not familiar with) in a precision scale model I may have spent two or more years building. Also I've been doing lots and lots of RC nothing recently and this seemed like a quick way to get back into things. And at $550, while that's not cheap, it's about the cheapest ARF available in this size. Yeah, it's going to look a little strange with that un-cowled radial up front.
Eventually, when I transfer the 770 to the Strutter (or some other WWI project) then I'll replace it with a 50cc gasser.