electricdave had the fan suck the heat off the motor for "challenger", whereas "voodoo" has a couple of fans blowing air across the motor and the controller. I'm not sure of the pro's and cons of each method, just that any cooling effect has to be worthwhile.
As for the 24v performance, "voodoo" has adjustable settings for acceleration,deceleration and top speed. Having played with these it is still underperforming,despite a replacement throttle and controller. Next up is replacement batteries, so just a thought - are your batteries giving enough oomph ?