These brushless motor kits come in a variety of flavors between 500-900? watts. I think some of you might even be running one? I'm starting to think they are not created equal. My question is if I want to vary speed with a manual knob (vs driven through software in CNC application) what am I looking at here? Many don't include it. Some call it potentiometer, some call it speed controller, some call it PWM controller. I see 3 wires on a little board looking thing. Would it be dedicated to the unit or something more generic?