hee hee... John, you forgot to mention the tell all test- Jack up a car with poly lower bushings and a car with rubber lower bushings. Using a pry bar , pry between the control arm and the k-frame right near the bushing/pivot. Compare how much the poly will allow the arm to move back vs. how the one with the rubber bushing won't allow it to move much at all.

It takes about 2-4 TONS of force in a press to install the rubber bushings into the arm , and the pivot into the bushing. The poly bushings install by hand.