We have more than enough battery capacity in GT12 so low current draw isn't an issue. WE use the 24k because it is really good motor and when sorted is fast through the whole run.
If the motor draws less current to give its speed them it generates less heat. That doesn't mean it is faster. As with any motor, find the right gearing/timing combo and it will go well.
In GT12 we find that combo on the 24k makes it arguably the best motor (with the Reedy 1S version) currently available. HTH
