Don't get hung up on any HP ratings! For the most part they are meaningless for model engines as few if any have ever been on any kind of dino. Zenoah is an exception.

I have (2) FPE 4.2 engines and for the most part find them to be good quality with performance to match their size. The one larger FPE I was exposed to seemed to be a bit of a shaker. About the only thing I don't like about the whole FPE line is the replaceable prop shaft. While a good idea, the execution leaves a bit to be desired. It is a rather small diameter for the size of the engine and I have had some problems with prop nuts seizing up or galling in the threads. I keep the threads lubed and at the first sign of roughness when tightening or removing the nut, it gets replaced with a new one. Other than that these engines are typical for any of the Sachs based engines. For similar style engines I like the Brison or Fox engines better. Due to the parts costs, all of these engines are now fairly expensive compared to the Chinese competition.