[KirkEvil]

I remember seeing poly spherical rod ends when I was in the market for LCAs. They were advertised as the benefits of metal spherical ends with the noise reduction of polyurethane.

Delrin is a nice material for some bushings, but it is brittle and does not do well with oil. It would not hold up the stress and grime a car would put it through. Polyurethane may be slightly less efficient, but it is durable and chemical resistant.