Questions bore reducers, lipos, and motor mount, e-revo

ok that explains everything better so when i use the hv 6.5 for a month or 2 i should use 2 speed and mech reverse. and with the mmm foc locked into second and motor reverse does this sound correct.
will the mmm have cogging problems i though it was supposed to eliminate them.

is there any other brushless application that also uses the clutch besides this?