its going to be a function of whether your desired speed can be achieved within the rpm limits of the motor, and whether the torque at the given ratio can give you the acceleration you want.
An 11" motor is BIG and HEAVY and has a lower rpm limit usually.... you may well be better off with all-around performance with a smaller motor and a transmission. just my .02
An 11" motor is BIG and HEAVY and has a lower rpm limit usually.... you may well be better off with all-around performance with a smaller motor and a transmission. just my .02