What do Suspension Parts do?
Springs - Performance springs will help keep your car from leaning different ways so much. They will help keep the car more level, also, when you go around turns, they are desinged to push correctly on the correct side of the car to help you keep control. The better the spring, the more control you will be able to keep when in turns and stuff. Stiffer springs will also keep your car from driving like a boat.
Shocks and Struts (Dampers) - If you had no dampers on your suspension system, when you hit a bump, your car would bounce up and down on it's springs. It would be a nightmare. A damper will do what it is called, it will dampen the blow from a quick/harsh movement of the suspension, such as a bump. Also, stiffer shocks and struts will help your springs because they are harder to compress in general, the strut/shock need to be compressed for the spring to move.
What that means is, for example, when you take a corner really quick, the stiffer the damper, the less likely the chances of one edge, or even a whole side of your car, of dropping or raising suddenly and quickly, thereby keeping your car more controlable by stabilizing and leveling the car.
Swaybars - Swaybars help keep both sides of your car level with each other. They are made of spring steel. So, a swaybar is actually able to bend somewhat, but, the more you compress a spring, the greater the force it will throw back. So, say you whip around a turn, without a swaybar, along with good dampers and springs, one side of the car may have a wheel that is being pushed up against the suspension spring, while the other may suddenly be pushed downward, just from the turn.
Now, if you took this turn with a swaybar, the swaybar would initially limit the movement of each side of the car as it tries to move away from the location that the opposite side of the vehicle's wheel is in.
So, it will help to even out the horizointal motion of the car. If your swaybar was super-thick, if you pushed down on the left front side of your car, the right side would also be forced down the same amount. If the swaybar was thinner, as you pushed down on the left side of the car, the swaybar would be fighting against the right side of the car's suspension spring, thereby making it less effective in keeping the car level horizontally.
Swaybars can both be too stiff and too soft. None of the swaybars available for the Beretta will be too stiff though.
Braces - A brace helps to keep the car body from flexing at key points of the car. Keeping the correct geometry to your suspension is very key in keeping your car on the road. The suspension does not function as well when it is bent in a shape other than it was designed for. And also, body flex can make it seem like your suspension isn't as good as it is.
GM supplies a upper strut tower brace, which will help to keep the geometry of that part of the suspension more accurate. You would be VERY susprised as to how well braces can work. There is also a lower frame brace available from GM. Since the bottom of the front suspension connects directly to the front frame rails, keeping them both in line with each other will also help the car's suspension stay in the correct geometry for it's best performance.
The top brace is about ะ and the bottom is around ฦ. Both available from GM, check the BNet FAQ for the two part numbers. I would highly recommend these two items as a beginning to anyone's supension modifications.
Polyurethane vs. Butyl Rubber - Alright, your A-arms, or control arms, whichever you prefer, are held on to the frame by bushings. Also, the swaybar is insulated by bushings, and has endlinks whcih have bushings on them aswell. In the rear of the car, the axle beam connects with bushings aswell. Replacing old rubber bushings will also help strengthen your suspension. The stiffer the bushings, the more accurately your suspension is capable of performing, it has less ability just to absorb something and let the suspension move where it shouldn't. Poly will basically keep everything in it's correct place better, and poly endlinks will help the responsivness of the swaybar.
That should be an adequate explanation of everything.
As for what would be the best suspension setup for your car, there are some questions that must first be asked. How hard do you want your suspension to be? Do you mind if your car rides very harshly over bumps or vibrates on the highway? These are all questions you will want to ask yourself before modifying your suspension. You will be sacrificing a comfortable ride for a harsh one, but, a better ride.
(Edited by bryan at 3:17 pm on July 28, 2001)