I know that you know how to finish the title, but if not, it goes like this: "If it ain't broke, don't fix it." Rarely is this more true than in airsoft. For the most part, an airsoft gun is pretty finely tuned. Alll the internal parts are made to mesh together and work in harmony.
Many newer players fall under the spell of higher FPS and they want to increase the FPS with a spring change before they ever fire their first round through their new acquisition. Now there isn't anything inherently wrong with this, but once that gearbox is opened, any warranty is voided. In addition, once any part is changed internally, you run the risk of other parts not being compatible, increasing expense and frustration.
Personally, I would take an increase in accuracy and an increase in rate of fire over an increase in FPS. Accuracy for obvious reasons, no matter how fast the bbs are traveling, if they don't hit the target, it don't mean shit. ROF is pretty obvious too. More rounds equate to higher chances of hitting your target. ROF coupled with accuracy = WIN!
Some problems with the FPS allure:
- Heavier ammo needs to be used to stabilize the flight characteristics. Heavier ammo costs more and is slightly more difficult to obtain than .20 or .25 ammo.
- The most common way of increasing FPS is with a spring change. In most airsoft guns, you need to open the gearbox to do this, thereby voiding any warranty.
- Stronger springs will decrease the life of your internals and play hell with a gearbox. If the gearbox itself gets cracked, your repair prices begin to skyrocket.
- Your motor may not have the juice to pull your spring. Can you afford to have to buy a $100 motor, just to pull that $13 spring? If so, hats off to you. If not, well, you know.
Accuracy can be achieved with an inner barrel swap. This is an easy change most of the time and often times you can do it yourself. Just remember, the tighter the bore of the barrel, the more important it is to keep it clean. Just remember that inner barrels are not rifled like real steel barrels, so you can only do so much about accuracy. A tight barrel, tuned with the proper FPS and ammo weight combination can increase your chances of hitting your target.
Rate of fire can be increased most easily by using a battery with a higher discharge rate. A 9.6 or 10.8 can give you a much greater ROF than a stock 8.4. Lipos are a whole other subject I will more deeply address another time. Suffice it to say, they will beat the shit out of your gearbox internals, but ROF can be ridiculous.
In summation, enjoy your stock gun for a while, chances are it will do you good if you bought a high quality airsoft gun. Only then, after you learn the characteristics of your particular piece, should you look for upgrades. But if you don't know what you're doing, leave it the fuck alone. There's nothing like putting together and tuning a jigsaw puzzle that used to be a decent gun.