RE: brushed or brushless, does it really make a difference ?
Brushless motors are more efficient. So, for the same current out of the battery you get more thrust and less heat.
Brushless motors need brushless-specific ESCs: the brushless motor is dumb, it needs the ESC to figure out when and where the bursts of electricity need to go.
If your plane is flying OK, leave it alone. Think about brushless for your next plane.