I did as EV2RTSE did, back in the 1990s, I drilled out the welds holding the old bushing in place, replaced with new ones, and welded them back shut. It takes a long time for these to wear out, and frankly, the old ones were not that bad, they just.... looked dirty and old. The bushings themselves seem to be a common type. They were, of course, "no longer available" from the dealer, but I found a set at my local auto parts store chain on the first attempt, that's why I think they are of common type. If your set in doing this, take your brackets apart, and you can measure the old bushings (or bring them) to a performance suspension shop, and they should be able to order an exact replacement. A bigger shop in a densely-populated area may have them in stock.