First of all, thank you for your help!
Now, I am not on a budget, I'm just asking if it can be done cheaper

From what I can tell, the super duper upgrade
yuhaoyang offered would still cost me less than a new JG, and JGs are very cheap around here.
So, if I upgrade the bushings (I have no idea what kind I have in there right now) and piston is should keep running? What about the gears? Wouldn't they get worn down, especially if they're cheap Chinese ones?
Another problem I have is trigger response time. When firing rapidly on semi auto the gun tends to jam. It sounds like the gear doesn't do a full cycle before I let go of the trigger, and I gotta switch to auto to unjam it. How can I fix this? I want to be able to use semi :P
Also, a question about barrels: Why does everyone use the 6.03? Why not put a 6.01 in there? Wouldn't it be more accurate with a tighter barrel? I know only one person who has a 6.01 and his AEG is a friggin monster. :O