Forget both an use my delrin lca bushing. Quiet and stiffer than poly and does NOT use the outer shell. Corner carving and rubber dont go together, sorry.
The outer shell is why I wouldn't recommend poly for most daily drivers. But that depends on how much effort, patience, resources the installers have.
The outer shells vary in thickness vs supplier and the way they were installed. I spent some time carefully smoothing and polishing the shell ID porting scrolls and small buffing attachment to try get the poly insert to slide in. Then it still didn't work. So next I very very carefully filed down the od of the poly insert. Made sure constantly measure the OD with venier calipers to make sure it was evenly round. Really could have used a lathe, but don't own one.
I ran a lot of the special snotty poly grease and if probably got 20K miles to this day on that setup I installed in 1997. And most of those miles where put on driving in LA city. West LA specifically. Mostly with .99" t-bars. When I go done there now with my 1.14" IMHO it's a little much. Fine in Simi Valley where I live now.
I'd go with Peters delrin setup if I replaced it now for what I do and where I live now. Better deal than that poly hit of miss stuff.
