on your 2nd question, I think for all but one of the rear bushings (thrust arm?) the bushings aren't replaceable, and I think you also have to remove the springs (which you are supposed to use a special type of spring compressor for that is $$$$) to replace any of the rear bushings.

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2005 Mercedes C230k sport sedan, 6 speed
1987 Porsche 924S - 968-engined track car