what upgrades are needed for a 10.8v battery?

in an m4.

i THINK mosfet and high speed gears, anything else?

Nothing is NEEDED. A 10.8v battery will give u a good rof but the higher the voltage the higher the risk that you fuck up your internal parts. If u want a good rof with decent fps as well as reliability here are some parts: SHS X-Mod Lightweight Nylon Polymer Piston w/ 7 Reinforced Steel Teeth, SHS X-Mod Low Noise High Speed Reinforced Steel Straight Cut Gear Set 13:1, g&p explosive piston head with x-ring, guarder cylinder head, guarder cylinder, Prometheus Non-Liner Irragular Pitch Airsoft AEG Upgrade Spring m120, g&p devil jet motor, ASG Ultimate Upgrade Steel Spring Guide with Ball Bearing, a new hopup bucking, Dean connectors, IF you want a programmable mosfet get the cheetah fet or the raptor, IF you dont want a programmable mosfet and just want simple gearbox protection u could get the silverback advanced fet.

Thanks for the heads up and good luck with your purchase of the battery.