What advisory??
What bushings? Those attached to the links that hold the rear wheel hub in place ?
Maybe you are talking about the bushings that hold the rear sway bar to the car?
It is hard to image the sub frame mounting bushings going bad.
If you are talking about the four large rubber mounting bushings that hold the rear carrier frame (subframe bushes?) to the main frame of the car. It would be easier to purchase an used subframe from a junkyard as it will have bushings/mounts already in place, than remove the old bushings and install new. You will need to remove the sub frame to replace the bushing if you choose to purchase just bushings and replace the originals. Either way it is a job I would not want to do without a lift.