[crazyjr]

I would think it would be better to gear for the speed you want on 5s, instead of running set speed for 4s and adding a cell and trimming down to 80%. the added gear would cause strain in the system and without full power to accelerate could cause overheat. Part throttle is the worst enemy of a brushless system and overgearing makes it worse. I'm still learning but i do know, from brushed racing, that you can't up the power and stick with the gearing from the lower power, bad things happen, trust me

as far as batteries i'd go with the maxamps 8000 because its not about the time its about the deliveryand with bigger density of power the better the batteries will handle the load, Besides 2 2s 2p batteries are lighter than 12 cells, by about 100 grams (maxamps 2s2p 8000 mah lipo, 370g. 6 cell NIMH 4400 maxamps pack 420g)