Originally Posted by airsoftjunky
Q#1: Is it worth it? Or is the V2 gear box to cheap for this?
I'm not sure which variant/vintage of the G&G body is in your gun but I can say that the plastic-body (opaque) G&G I got last spring (the Diablo) had quite nice internals which I've since re-used in other builds. The gearbox shell I have even has radiusing around the borders of the cylinder window -- stock -- so this wasn't some careless design.. You can almost certainly improve the performance of your gun with a few simple updates. If your budget is 200-300 without upgrading the body, you can pretty much cycle all the internals to new ones if you wanted to.. But I don't think it's necessary. You should do a budget build and see how far you can make, say, $150 go.
Off the top of my head, and having worked with a G&G mechbox myself, I would recommend the following:
1) Clean mechbox, re-shim gears, re-lube (cheap, get the Modify "advanced" shims for 4 bucks a bag)
2) Better bushings (cheap)
3) Spend a ton of iteration time on improving the seal of your compression system: check compression of cylinder, piston's o-ring, Teflon tape (cheap) around the cylinder head if necessary, check the nozzle goes into the hopup far enough to make a good seal, etc. Seal your hopup better, consider doing things like the tooth floss mod (again, cheap, see Maekiii's channel on YouTube) or Teflon tape, etc.
4) Motor upgrade. I was really quite disappointed with the stock G&G motor, if you can throw a nice neodymium motor in there (re-shim if you do..) you'll be pretty surprised. Don't spend more than 50-70 bucks if you can help it, in that range there are some great motors.
5) Rewire from Tamiya to Deans (cheap)
6) Check piston's angle of engagement, consider shaving a tooth if you have to correct it (might need to pick up a cheap file for this step).
7) Clean your trigger contacts
8) Install a simple and inexpensive MOSFET (some other people here recommend stuff like the Extreme-Fire SW-Comp, which is pretty affordable) so that you can use LiPo batteries without charring up your contacts and can direct more juice to your motor
Some folks will tell you to try a tightbore barrel, which might also be a nice budget update that might go far, though if you're happy with the accuracy as it is, you might want to skip it in favour of making the gun shoot harder, faster, quieter, and more reliably (which my above upgrade suggestions would focus on).
You should keep us up to date if you decide to go through with this stuff