Is everyone using those hard plastic bushings in their 4 bars? They don't seem to last too long and give a harder ride. Do you think if someone made a mold to pour softer urethane or rubber directly in the 4bar end incorporating the center sleeve in the mold, they would be better? I can't see why this wouldn't work. It would necessitate repouring them if they wore out. I am just looking for a better ride and longer lasting bushings.