Regarding RC engines on CL planes, I found that RC engines work well.

I replaced the OS Max 15FP-S and 8x4 Masters prop with an Enya 15-III TV and 8x6 Masters prop. With throttle wired wide open I found I was getting the same lap speeds. The plain bearing Enya cross scavenge HP peaks out at a lower RPM than the sport Schneurle ported OS.

These Enyas are powerful little rascals.