RE: Strongest 46 engine
So it has to be the OS 46AX. I have 2 OS 46 FX, one with a tuned pipe.
The pipe will give you more power in a certain rpm range, but also increases fuel consumption, I don't know how important run time and weight will be for you.
Also the prop size will be very critical as well as the fuel type / nitro contend. The pipe makes the engine more touchy, harder to tune. It might be necessary to adjust the needles between flights to get the engine to put out the most power. A rpm meter helps a lot