For: Echo 1 Long Type torque MotorUm, i really don't think this motor can pull an m120 at 20 rounds a second. I've saw an echo1 motor, and its not all that great compared to the high end motors.
My friend owns a CA m15a4 carbine with the following upgrades.
systema hop up chamber, with systema buckling
systema magnum motor
systema 6.04 tightbore barrel
area1000 spring guide (doesn't make a huge difference)
9.6volt 2800 mah battery (not really an upgrade, but a HUGE battery)
we chronoed his gun, it was roughly around 380 FPS with a .2 bb. Then we changed the chronograph to rounds per second, and it was pushing 20 rounds a second, with the magnum motor, and one of the highest powered 9.6 volt batteries out there (this is a mini type at 2800 mah). Also if you recall, CA wiring is preupgraded to 16 gauge wiring, so there isn't really any need to upgrade the wiring. And like i said, we were getting around 18-20 rounds a second with the best motor out there (the magnum), which cost about four times as much as the echo1 motor. The echo1 motor can pull an m110 like an EG1000 can pull an m120. Like you said, its not really an upgraded motor, but a very good replacement.
Now, this motor is good don't get me wrong, it is a very solid little piece of work, but when it gets compared to the magnum, the hummer1300, or even the little EG1000, then its not all that great.