OK i want to fully upgrade my gearbox, would i need to change the receicer to an all metal one to handle the new gear box? and could some near possible help me rewire and build the gearbox when i begin the process? Iam yet still a noob to airsoft so please bear with me, i would like to know what part is what and where they go. I want to know the best possible parts to put in it as well, so could anyone give me some advice on what the best parts are? oh yea its for a TM SR-16, thanks guys Jags87