Your going to have to reuse the stock CRX DX in car harness pretty much no matter what (it would be a real pain to even remove it, much less wire in a new harness never designed to go in that car). This requires you to stick with the CRX DX engine harness or it won't plug into the in-car harness. You will however have some work to do to that harness, specifically adding wires for 2 more injectors, VTEC, 4 wire O2 sensor and others (I don't know specifically what will need to be done, if you have old Sport Compact Car issues they did a DPFI to MPFI tech article that was pretty damn good, their website might even have it sportcompactcarweb.com). You will also need an non-OBD EF to OBD I EG conversion harness to plug the P28 SOHC VTEC ECU into your in-car harness. You'll have to reuse your stock tranny (or shop around for an Si tranny, the better gearing will help that D16Z6 get moving).

If you really want cheap as possible, you can also do what I recommend to the guy in the other thread, swap intake manifolds and run the D16Z6 as a non-VTEC DPFI engine. It will make less power but if price is the deciding factory, it will be cheaper. If your doing that, I'd say just go grab another '88-'91 DX engine though, probably cheaper yet.