With the 123 distributor, I used the red coil (1.8ohm?) and bypassed the ballast resistor as the mfg recommends. You can leave the resistor in place and just use a separate wire to bypass it. That way, if you ever want to install the stock distributor, it is easy.
I also used the stock wires and NGK plugs (forget the number at the moment). You can also increase the plug gap to take advantage of the better spark. Some people on this site have said .035" and I currently set mine at .033". I am going to experiment with .035" soon though.
I love the 123 and wish I had changed sooner. Starts great, runs great, dead on with the timing and no maintenance going on two years now.