I currently have a g and g full metal m16a3 body and front assembly however it does not have a gearbox. I am planning on using it in a DMR build. My first question is can the shell withstand a Systema m150 if I radius it and install a 70 d Sorbothane pad. My second question is can SHS parts be installed without major modification . I plan on replacing the piston, piston head, cylinder, cylinder head, air nozzle, spring guide and gears with shs, guarder and Systema parts. I also plan on installing a Prometheus 509 mm 6.03 barrel, rhop and a modify hop up chamber. I also plan on adjusting the aoe, shimming and doing the usual air seal modifications. The reason I am buying a full gearbox is that I know jg has quality parts and I will use them in other builds and repairs so they will not be going to waste. That brings me to my third question is it cheaper in the long run if I buy this drop in gearbox and buy the parts in what I would guess could call bulk than if I bought them individually in the future. Thanks for your help.