It was the bashing into stuff I was thinking about. Travel not in the direction or beyond the limits of the basic suspension design. The same reason rally cars don't use 22"s.
The sidewalls save the rims in the extreme bashes. The bump stops and top hats protect the struts.
Maybe Group N bushings would all be Delrin if permitted??? I'm not a Rally person either, so what do I know, just thinking that very hard bushings may cause other things to start bending/braking.
You have obviously worn some out, just suggesting you think about what might have worn out or broken instead if those had been solid? While your car is not AWD, I would ping the WRX/STI teams and suppliers and ask the questions.