On my 89 DX that is...

So far I believe the CRX Si's rear discs or a 90-93 Integra's rear discs should work right?

And for this I need the trailing arms and everything attached to them respectively. What else should I need?

If I wanted to get SS Brake Lines what car would I get them for?

 

This: https://honda-tech.com/zerosearch

And my take on rear discs are, if you don't have 'em, don't worry 'bout 'em.

 

You will need the rear trailing arms, 90-91 CRX Si e-brake cables and proportioning valve. You may also want to pick up the rear sway bar as well. From what I understand the hatches have the necessary welded nuts to mount the sway bar. As far as the stainless brake lines 90-91 CRX Si lines should work fine.