Bushings?

So, now we'll move from Cylinders to Bushings I guess
What do they improve? I know how/where to put them in,
But why do we do it?
And when is a good time do do it?
Is there noticable improvement in whatever it is they improve, or are they just kindof Reinforcment for something High Speed or High Power?
Also, this is just an example but.....
http://www.airsoftgi.com/product_info.php?products_id=5794&osCsid=rsu95ukscuan7512mju29chqh4
Are these Good, or Bad? if so, what makes them Desirable or something to keep away from?
What I'm asking is, what makes a Bushing good or bad?

they look good, not sure what they do tho

Solid makes them better

bushings make it so the gears spin more smoothly than if they spun against the gearbox. Brass is very nice right away but i think they are known to ware away faster than other metals. Not 100% on that last part tho so do some research

G&G is upper mid-level i wouldn't say its high level but almost......

The original nylon bushings are a week point so if they cracked they would cause the gear to shift slightly between every shot causing the teeth to strip over time. Metal bushings help reinforce it for torque to pull a higher spring or some like bearings remove friction for more RoF.

There are no disadvantages to buying bushings. Overall they make your gun MORE upgradeable.

Ah, I understand. Thank you for the help Everyone.

Bushings,

There are all kinds of Bushings, Nylon, Brass, Alloy, Steel, Oil Channel, Oil less, Bearing....

The Nylon and Brass are usualy found in your standard Gun, they are the cheapest and in a standard configuration they will deliver great performance, the biggest problem, they wear out relativly fast.

Everything after that is for improvment, replacement or for Tuning, each have their benifits, and weak areas, not every typle is designed for every level of tuning, or to be used with every kind of gear set, i.e. you may not want to install Bearing Bushings in a Gun if you are running at the M150 level or above, there are Bearing Bushings on the Market that will handle that amount of power, but they are going to cost.

The whole reason for the bearings are as stated above, to hold your gears in place and to allow for proper alignment of each individual gear.

Very nice....do you think you could give me "list" of each bushing and what type of upgrade/setup you should use it for?