It is kind of difficult if the inner sleeve if there is rust (on the front, my driver side bolt needed to be cut out after all the exposure over the years). Depending on how easy it is to access the bolts at each spot determines half the battle.

It is definitely not something you need to replace, as evidenced by how few people have seemingly done it on this forum, but if they are cracked, they are old. As I want to drive this for many more years, I've happily taken on the process of upgrades even for the small stuff, like the condenser frame mount bushings lol. With the best online discount, you'll pay around $35-45 per bushing for OEM.