My m14 project.

I am thinking of buying a M14 to work on, more than likely a echo 1. i know how everyone rips on Echo but their m14 is solid stuff. Great fps out of the box almost 400 actually and the stock feels like the real deal no cheap plastic. Everythingis full metal so that is great. Anyways to the point. I do not like the fact it is a snub it just doesnt look right. I am gonna put a TM outer barrel on it so that solves that. Now for internals I really wanna put a M140 spring in it so any suggestions for a good reinforced gearbox? Then a new air nozzle, hop up bucking and a PDI 6.01 inner barrel. And for the battery a lipo 9.6 or 10.4 the reson for that is cause ( if it makes sense) I want no delay wen i pull the trigger, and that is because i want to be able to semi auto a lot faster ( I like semi auto because I feel more precise and in control than in full auto) Its also pretty sweet when u pull the trigger once and it ends up popping someone in the head haha that makes the game. Any suggestions would be appreciated thanks.