One more data point:

I put derlin bushings in over the winter.

Old ones were original, and the rubber was pretty much toast.

I really don't notice a whole lot of difference.

Maybe the old ones were so hard, that they were the same as the new ones?

Maybe I don't push it hard enough or often enough to really tell?

Don't know. Glad to have them in there, one less 'really old part' on the car.