Yup..I did it to my 90 hatch..I used a 97 rear disk conv on my civic and it didnt fit...You will have to modify the wishbone tingy @ the end...<---I suck..
anyways...I forgot how i did it buy it can be done with alittle mod....
I'll try to get some pics for ya as soon as I get back from Canada..<---Yeah!
Use a rear disk setup from an older Integra or crx...Its a lot less work...<--
i have dc rear disc on my rex. its a bolt on process, you have two ways of doing this
1. using complete trailing arm(minus what estorvito said, you will use your existing wishbone thingies..lol..) or
2. unbolt spindles from your trailing arm and replace with integra spindles
either way envolves roughly the same amount of work.. be sure to have 90-91 crx Si e brake cable's, your drum e brake cable will not fit