We have a plug-and-play 36 Volt 750 Watt controller for the Razor Ground Force version 5. It is item # SPD-CT312C1
Here is a link to it: https://cart.electricscooterparts.com/speed-controller-for-razor-dirt-rocket-electric-dirt-bikes-mx500-version-1-9-and-mx650-version-1-7
The CT312C1 controller has one extra brake lever switch connector than the original Razor Ground Force version 5 controller, which can simply be left disconnected when installing the controller. Other than that the CT312C1 controller will be a direct replacement plug-and-play controller for the Razor Ground Force version 5 go kart.
We do not have a 48 Volt plug-and-play controller available for the Ground Force V5, however we do have 48V controllers that can be custom installed in the Ground Force for upgrading it to 48 Volts. If you decide to upgrade to 48 Volts please let me know and I will be glad to recommend a controller and wiring directions for that modification.
If the Ground Force Drifter was upgraded to 36 Volts then the motor, controller, battery pack, and battery charger would need to be changed. The throttle would also need to be changed in order for its battery meter to still work.
However to upgrade to 350 Watts only the the motor needs to be changed. The Watts of the motor indicated how much power it has. A 24 Volt 350 Watt motor has the exact same amount of power as a 36 Volt 350 Watt motor, so there is no good reason to change from 24 Volt to 36 Volts when upgrading from the Razor Ground Force Drifter's original 250 Watt motor to a 350 Watt motor.
Our item # MOT-24350X2750 is a 24 Volt 350 Watt motor that could be installed on the Ground Force Drifter without the need to change any of the other electrical parts. The Ground Force Drifter's original speed controller is rated for 30 Amps so it will have no problem running a 350 Watt motor.