Uhhh why isn't the Addco in the back an upgrade? I don't know if you can get urethane bushing for the stock rear bar. I believe the bar diameter is an inbetween rear size, like 17mm or something funky. Also I don't know if you can get a urethane bushing for the stock top shackle type end. The lower part shouldn't be a problem though. I would go with the PSTs if they are available. The polygraphite should theoritically be less squeaky than the urethane energy bushing.