My buddy has a m4 which he upgraded and got a matrix 3000 motor. He shimmed it, but isn't that experienced with shimming. Using a g & p gearbox shell, we tested it and it destroyed my lipo(7.4 and 11.1 with deans, got all puffy/liquidy inside. So we installed a mosfet and silver coated wiring, it still did it, but not as quickly. Any ideas guys?