This is Why i made this conversion to my MMM.
Now i can clean it in 1 second and my temperatures are very very low without a fan. I use it in a e-revo with 6S (flightmax 40c) medusa 36-80-1600, 17-18 pinion and 65 spurgear.
Traxxas has built a plastic case so big and fit that the air circulation is near zero also with the fan turned on!!!
Maybe this summer i'll mount a fan on but i doubt it.