St Grabriel finds the T238 39000rpm Brushless Motor handles his M140 spring better as he upgrades his AEG... "Upgrade on my M4. I changed old good SHS high torque motor to T238 beast with 39000rpm. Now it's easy handles M140 Guarder spring. And an example - SHS high torque motor with 12:1 gears and less powerfull M120 spring."