As I think was stated, sort of, bushings should not squeak. Neither the exterior or interior of the bushing should move. If they squeak they are either shot or not tightened enough (or shrank = shot).
Many have replaced and tightened their bushings with the use of a lift. If you tighten the bushings without the vehicle sitting in its normal ride height position ...and you tighten the bushings down ..you put a preload on them that makes them want to "lift" the vehicle. On heavier cars it only wears them out sooner, but on my Fiesta, for example, it caused camber wear on a vehicle without camber adjustment. I had to take it to an alignment shop and have them loosen the bushings and cycle the suspension and then retighten them to fix the situation that the inexperienced mechanic had created.
Neither shop, btw, had a clue as to what I was talking about ..but the alignment shop acknowleged that the front end of my car hadn't lost any weight and there was no other plausable reason for the camber wear.
It fixed the problem.