MM Motor Cooler, Brushless???
 

Is there any reason the MM motor cooler can't still be used in conjunction with a brushless motor? We used to use them with brushed, why has the trend died? Or what it just a gimmick?

I don't see why not. I use one from time to time when I'm racing outside when it is super hot and qualifiers are going by really quick, to help cool my motor back down. When there isn't much time for the motors to cool off before you hit the track again, I think it definitely has its value. As far as a performance boost with brushless motors, I have tried freezing them and didn't really notice a change to be honest. So basically I just use mine to cool between rounds when needed:D