What is the difference in suspension set up here. (Bushing question)

[Qualitywires.com]

I see some bushing kits going for $300-$400 for the entire set up.

Energy Suspension has them for way less but not sure of what the big difference is other than price.

Summit link to their item:
http://store.summitracing.com/default.asp?target=/product.asp&p=2226&searchtype=ecat

the entire set up would be less than $100.00 and they are polyurethan bushings.

Can someone give me insight of this?

What are the good's and bad of swapping out rubber for poly or any other type of bushings. (I was told that Poly would require more alightment due to losing its hold and also could bend the frame if you hit a bad pothole.)

 

[Miles B]

I think poly squeaks more and gives a harder ride.. the rubber is there to bend for the axial movement, *and* to take a bit of up and down shock I guess.

 

[jrkermode]

Bushings run the gamut from plain old Buna rubber, to higher durometer polyurethanes, to Acetal (trade name Delrin), to spherical rod ends. To compare flexible bushings to one another, simply ask what the durometer is. The higher the durometer (bigger number), the harder the material.

All bushings will take a set after use, requiring you to periodically re-check the alignment

The idea behind stiff bushings is preventing the control arms from wiggling around. This is important if you're running slicks, because slicks are sensitive to the small alignment changes that result from the wiggling.

Street tires aren't nearly so sensitive to small alignment changes. So, all you really achieve on the street is the undoing of several million dollars worth of noise, vibration and harshness testing (make the car more uncomfortable to ride in).

 

[KepRght]

undoing of several million dollars worth of noise, vibration and harshness testing (make the car more uncomfortable to ride in).

Bah, stiff bushings are the only way to go if you actually push your car. The several million dollars worth of testing was used so that your grandma would be happy picking up eggs from the corner store.