Hi the 24v conversion gets rid of the standard POD and control box. Most use the 4QD Uni8 controller and speed throttle. The use of the standard motor gearbox is used with additional cooling. Slowly on ramping the speed, as to not put too much strain on the gearbox or it will fail.
You end up putting twice the voltage and thus more current through the motor which in turn upto twice the speed. Hope this helps.
Lance