Disc brake swap!?

When i was swapping my 91 civic dx tranny for the si tranny i was told you can swap the rear drum brakes to disc brakes by buying the disc set up off another honda (not sure which). Is this right? apparently they bolt right up. can anyone tell me which car the i need the set up off of? and if its as easy as it sounds? And for you Honda owners check out our website at www.kamloopscivics.com or the forum at www.intencity.cc