hello. need some advice on upgrading my polarna m4 750 watt motor to a 1000- 1500 watt motor. the polarna doesnt have regular spokes. it has the six spoke wheel. the motor slides in to the housing. without changing to a spoked wheel on the rear, does anyone have the knowledge of a motor that will fit the wheel housing. polarna doesnt respond to inquires. if you have advice or have done this,I would appreciate your response.