WTF ok.......Yes, you will be fine with 6 cell and SB hybrid motor. What I was trying to explain was how to figure out whether you'd be OK on your own. It's all about current draw. What makes your FET's OK and NOT OK are their current carrying capabilities, and the voltage/motor setup you have.
Use a DMM and connect it in series with your motor and the power supply you will be using. Read your current draw and know that that's the same no-load current draw that your FET's will be carrying to your motor when you fully throttle. If the current seems excessive, THEN UPGRADE YOUR FET'S. If not, then DON'T UPGRADE YOUR FET'S. SB's have to be one of the lowest current drawing motors out there. Unless you change the armature that is........