It's the "Powerup 480 Plus" motor, listed and linked on the headsuprc page for the Formosa-II. I've never had a bad motor from them... in fact this is the first time I've bought a plane from them. (headsuprc, that is.)
I plan to use GWS Naro Pro servos on it... I've had 'em around forever, from some other project that never got built.
I had some radio issues with my 2nd Mosa-II as well, but I can't really blame the plane. Radio problems seem almost impossible to diagnose or explain away, and as I recall it was a time when many of us were experiencing radio problems at that particular site. Or maybe it was a rash of poorly set-up planes, and we've gotten wiser since then.