I went through this job this past spring/summer (replaced trailing arm bushings, but not the actual trailing arm). Here's my take:

1) I would consider it, at minimum. Initially, I wasn't going to. The passenger side looked passable. But, the driver side mount broke apart easily by hand when I removed it. So, I was forced to do the job.

Subframe mounts weren't bad once I'd gotten that far. I bought the cheaper mounts (Meyle?) that a lot of people report fitment problems with. I came up with a press tool of my own design for the subframe mounts and inserted them with the help of Sil Glyde. I got them in all the way - perfect fitment.

So, if yours are AT ALL questionable, I'd do the job now. You'll never have better access.


2) I'm of the opinion that replacing the whole subframe with trailing arms would be more difficult and probably unnecessary. Here's my reasoning:

-once you have everything necessary removed/disconnected, and the subframe lowered, then there are only two nuts/bolts on each side holding the trailing arms on. So, by the point you have access to replace a trailing arm, or the whole subframe/trailing arm assembly, you're only two bolts away from replacing a trailing arm.

-in order to replace the subframe, you'd need to wrestle the old one out from under the car and wrestle a new one underneath the car. Also, if you source it yourself from a junkyard, you may need to remove it from the donor car yourself while at the junkyard, and then truck it back to your workspace. That's a lot of work and a lot of moving you may not need to do, on top of the added cost of a lot of other (possibly) unnecessary parts.

3) At minimum, I would replace trailing arm bushings on both sides if you're replacing a trailing arm. (Unless the old ones really have no noticeable wear/play. You may or may not also want to replace the rear differential mount and/or the rubber spring pads/spacers.