I have Mario's aluminum bushing. I have the poly ones too, but have not installed them.
It took me less than an hour to install on my own with a full set of tools, a floor jack and jack stands with minimal lighting.
My drive train tightened up considerably. I now have slightly less understeer coming into a hard turn. There is no discernable vibration, harsher ride, or extra noise generated from this install. Full throttle accelaration is much snappier with less "mush: that before.
I would recommend the bushing for anyone even considering changing theirs out.
good job, Mario!