I am thinking of putting some upgrades in my f2000. I've been looking around and i'm thinking of putting some high-torque motor + high speed gears for good trigger response and good rof. I'm planning to use either an m120 or 125 spring for around 400 fps (which can be adjusted on the fly if too hot) which is why i want that motor. I am going for reliability here so i am thinking a medium-high discharge 7.4 lipo. Anything i should change? What other parts should i reinforce? This will probably be done when i learn to shim.