Those electrical motors have several types, wich usually refers to the type of can they use, so if you can find out wich type is on the G25 and DFGT, its easy to get one replacement because the same type of can always has the same size and even the same holes to hold it down, after this the only thing is respect voltage, amperage, wattage and your down.
Those are Radio control car motors, try to find also Slotcar motors because theres a lot of makers and all type of different cans.