Have a 95 Z28, that's pretty squeaky from the rear. I think it's the rear suspension bushings, but I'm not sure what to do about it.

I think it will be easier to buy something like this:
http://www.lmperformance.com/4346/17.html

But I can't find any reviews of it. Has anyone used it? Is it ok to replace the rear arms and not the fronts?
Hotchkis Lower Control Arms (http://www.lmperformance.com/4346/17.html)
Hotchkis Lower Control Arms (http://www.lmperformance.com/4346/17.html)

unless it's already got poly bushings in it, i don't think it's the bushings.
i think there are rubber spring isolators that go between the spring and body- if they are gone, then it might squeak like that.
it's also possible that your exhaust is rubbing something- either the torque arm or panhard bar would be a good place to look.

It's most likely the sway bar bushings. It's a really common problem on 4th gens to have them squeak. Not much you can do about it aside from grease them every few weeks.