I don't know how much CYMA's and JG's are these days but you could get an Aftermath Kraken or whatever. I do believe they come with CYMA gearboxes under the shell just cheaper externals and a good gun to tinker with.
And +1 to what TC said, a better bucking makes a world of difference and it's not too hard to replace if you have some tools and technical know how and can read and follow instructions in a guide. You don't even have you get into the gearbox just into the front assy. and replace the bucking on the barrel (might I suggest a Guarder Clear bucking which was what everyone was recommending back in the day, or look to see what performs well these days, I wouldn't attempt an R-Hop mod though just replace the bucking).
ಠ_ಠLess QQ more Pew Pew
READY TO >> RACE