G36C upgrade plan help

Ok, I would like to upgrade my jg g36c without opening the gearbox at all. What I am looking for is an increase of overall performance for under $200. I was thinking of a tightbore barrel, systema bucking with a scs nub, and possibly a MOSFET. I would like some other suggestions for this project. I also need to rewire the gun because the wires are jacked up pretty bad, would this be possible without opening the gearbox? Also, does anyone have a reccomendation for a MOSFET that has fire controls like a burst setting? Thanks to anyone that helps with this project.

Rewiring requires opening the gearbox. The rest does not to my knowledge

get a new gearbox there you go lol

^Not a very helpful comment there, but yes rewiring the does make you open up your gearbox, and as the person above me said, a new drop in gearbox would be one of the easier ways to upgrade your gun with out having to open the gearbox, a new motor could also help pending on if you want high rof or high fps. TBB's are great for upgrading accuracy and range of effectiveness, and it also gives you a boost in FPS, due to the air having less space to go other than at the bb being shot. As for hop ups I don't have alot of knowledge about them other than you'll want a harder bucking for high fps guns and soft for low fps guns