different motor for muggy on 6s

[riverat1540]

i was currantly running my muggy on 5s 5000 w/ mmmv3 neu 1515 1y geared 14/46 and needless to say runtimes were short and the pack was getting hot and the motor was a bit to warm for liking as well. over all it was just something torn from my crt that was enough to show me i really like this thing, the drivetrain is awsome, and so im looking to know what motor i should run and i want 6s so i can gear down if need be over running hot, so im thinking the 1521 1y is my best bet. will i have any concerns running this motor? also if im ordering new i might as well get the 8mm shaft since mike is now making pinions i see. i just want a cool running setup and great runtimes geared for about 45 on 40 series yet still room to gear down for 420 series