Makes the motor work less, Faster activation and feeding. More efficient on batteries.
None at all.
When you put it in, you might notice it is rubbing on something. inside the motor housing cut the two tabs that hold the stock pulley in place. that will make your hopper faster than with the pulley rubbing on it.
As soon as i turned it on my B2 suddenly activated. Mode 4 does that job that it would do on mode 6. And in my B1 it does the work on 1 that it would do on 3 stock. Faster activation. you dry fire and it suddenly spin. and fast. it picks up quick and goes fast. very nice. i love it.
Makes your hopper faster, more efficient, longer battery life. A+. Go get one. NOW!