the difference between 300-400 is overall negligible, you're not getting any crazy range increases with a higher fps, a TBB does increase your FPS but that doesn't mean that FPS = Range. You'll honestly be fine with 300 FPS on a stock TM gun, the hopup is doing most of the range/accuracy work. If you stick a M90 in your JG ofcourse it's going to be stuffty but a 320FPS gun with good airseal and a r-hop is going to outrange your CYMA with a "new bucking and nub".
The single most important factor to range is hopup, not FPS. Increasing your spring gives you an increase in range but with the caveat of degradation of your gun, instead of sticking a higher spring in your gun just r-hop/flat-hop it and you'll get better results than you could ever get with a simple spring change.
@Zloff, the bushings don't matter, they use Nylon bushings which are just fine for sub 350 FPS. tms dont shoot at 100fps what are you saying lol, you're completely exaggerating what I'm saying
Once again, FPS is not as important as you want it to be, I'm sure everyone thinks they're an awesome airsmith super good tech because they open their gearbox and shim and change springs but the reality is that there's much more to upgrading than what you think their is.
Basically
FPS = Minor/Not major contributor to range, obviously main contributor to velocity
Houp = Major contributor to range
Barrel/Airseal = Major contributor to accuracy
Motor/Battery/Electrical (Wiring, good trigger contact, mosfet) = Trigger response and ROF
Gears/Piston/Bushings/Shim/Etc = Reliability and performance overall
Doing things like making sure you have correct AOE, a good airseal, and changing your tamiya to deans are all upgrades that are more worth it than FPS. I'm not denying FPS as an important factor but stop obsessing over it, every post is hurrr my gun shoots at XXX FPS.
edit: let's just leave the conversation at this instead of clogging up the thread with this discussion, if you still care about it feel free to pm me at which point i will not respond