The Nissan Path

So I am preparing to replace the LCAs on the rear. I'm not too worried about the work or the how-to; I have read up, and have lots of experience cursing at rusted bolts and smashing my hands on sharp things while lying under various vehicles trying to oil, torch and saw them out. (I have previously restored British sports cars, so I really know how stupid this can get).

But what I need to know is: What are the definitive tests that will tell me whether I have to replace the arms or not? For me, frozen eccentric bolts (meaning no alignment possible) is the reason I am doing this. I have Ranchos on all 4 corners, and AirLift 1000's in the back, Michelin LTX/MS2s, and an increasingly squirrely ride despite all that, which I know means alignment issues, which can't be fixed without new bolts.

So: Replace the lowers because I may as well after sawing the shit out of things to change the bolts?

Same for the Upper control arms?
What about the spring carrier arms (the "aft" LCA)?

They all have bushings, and I assume they are all a giant pain to replace. I can't tell from the crappy parts diagram whether there are eccentric bolts everywhere, nor do I know if adding some where there aren't any is a good idea for better adjustment (like we do on the front).

Summary info and advice appreciated. I'm prepared to do the whole thing with new everything, I just want to know what is best practice.

Thanks in advance.

The front lower control arm has one eccentric bolt and one regular bolt. On the left side, the regular bolt will not clear the gas tank, so I cut it out and installed the bolt backwards as opposed to removing the gas tank. The rear lower control arm has a single eccentric bolt. FYI, the eccentric bolts are the same part numbers as the ones used in the front to correct the camber/caster. I would confirm that they are seized before replacing them. On my 06 LE, none of the bolts were seized even though it had 140,000+ miles on them. On my 08 SE, the rear suspension, front control arm bolts were seized; the rear suspension, rear control arm bolts were "difficult" to turn, but they did turn (with a lot of rust penetrant and a big breaker bar!).

That's good info, thanks. The dealer checked the alignment as part of a pre-trip safety inspection, found the rear was out, and told me that the bolts were seized. I don't know for sure how badly seized, but we're about to find out I guess...