You should be straight using DA parts. You can upgrade to the DA knuckles and brakes and it will bolt right on, and it should give you a little bit of positive camber (good if the car is lowered. It will bring the negative back out some). Just make sure you take rear trailing arms with everything on them (but you can use the Civic LCAs if you want), the proportioning valve, the E-brake cables (they will be a little long but you can tuck it up with the gas tank), and the hoses that go from the hard lines to the calipers. Or, if you would rather, you can get Stainless Steel brake lines for either a DA or a 90-91 CRX Si with rear disc. I would probably go with the CRX Si ones, myself. The rear calipers, discs, and rotors are the same from CRX, to DA, to DC, ETC. Other than that, everything bolts up. Actually, you might be able to use the brake master cylinder and booster from the DA too to give you more breaking power, but I would need to do some more checking on that.

Does the DA you are looking at have ABS? It is a lot less work if it doesn't. If it does there are some sensors and stuff you have to remove.