if you want long runtime use a 9xl
for more speed use a 7xl
and for somewhere inbetween use an 8xl
the warrior 9920 will work with any of those motors the 9920 can handle up to 20 cells and 99 amps continuous also when using more than 12 cells you will need a ubec or reciever pack and instead of using a fiego motor get a BK because they have better bearings