I have the nylon bushings installed them 10+ years ago, no squeaks and stiffer than urethane supposedly.
They were only a few dollars more than urethane. I think Dick Ross recommended them to me.
Never heard of the nylon. I'm surprised to hear they hold up so well. I would have thought they cracked eventually. Looking back on my rebuild I went with stock style bushing there and polygraphite everywhere else. I largely based my decision based on the A body guys here.
https://www.forabodiesonly.com/mopar/threads/lower-control-arm-bushings.495665/
