RE: Engine Questions/Decision
Most people never wear out an engine, but do damage by running lean, in dirt, or crash. Cheap fuel and lean runs get most.
If your interests are in boring holes in the sky at high speed, go with the ABC technology. If you are flying along at low power settings, a ring engine works better.
Nothing on this size engine is going to blow up at the peak power rating rpms. But you have to match the prop to the airframe.