ORIGINAL: kid chuckles
Mount you a brushless of the same size. I think they have a 480 geared. So a 480 brushless would be more power. Mounting might be a trick though.
the typhoon already has a brushless motor....both the first one and the new one. Buy a brushless outrunner maybe an axi, or even eflite, it already has the eflite 25amp brushless programmable speed control so any motor that doesnt draw more than 25 amps should be fine. you may have to modify slightly to mount but not a big deal.