I always heard the graphite bushings are best but also more expensive. The graphite acts as a lubricant to reduce binding and noise. Just what I heard.
Urethate bushings will give you the squeeks. Highly annoying. Polygraphite has graphite impregnated into the urethane for lubrication and they stay quiet.
Thanks for your feedback on this. I do apologize for bringing up an old topic. Just need a quick answer. I knew the answer before, but like I said its been years.