I just installed the polygraphite bushings in my pivot bushings too, and the machine shop I took mine to did the same thing to my shells. No big deal, I just bought another replacement rubber-type pair for about $20 and knocked out the rubber and kept the shells.
Oh, and just for the record, what you're calling "torsion bars" are actually the axles, or I-beams. Torsion bars are actually round bars used as front springs in some cars, most notably the '60s-'70s Mopars.
![Wink ;)](./images/smilies/icon_wink.gif)
But we knew what you were talking about.