They chrono-ed before hand and got 407fps (MAX) then after the spring change it was 300FPS range. They just tried the spring that was one level lower.
It was the gear attached to the motor that was stripping. Also another problem was the seal. They tried adjusting the motor height but nothing worked (clock/counterclock). There was no sound in either case.
In any case to fix everything so that it works (probably) would take just under $200.
As the guy said, just going to trade in.
Thanks for your input! I hope no one else will have problems with their King Arms M4 but if they do, I hope the post here will help!