Julian wrote: lol...buying a working gun and just leaving it the hell alone is a pretty solid route to take.
+1. I saw this microswitch gearbox and I didnt like the look of it at all. Its an uber cheap Chinese gearbox, witch will give you much more hassle than its worth. I can see the shell snaping with its stock spring.
I like the Ares m4 that has the quick spring change feature and metal body if your die hard for that feature.