The Pertronix is a very easy install. I would suggest you get their recommended coil as well; I went with the Flamethrower II model in classic black.
You need not worry about ballast resistors; they are not required. You do not need to remove what you might have, however— I left my old ballast resistor in place and actually use one side of it as a tie point! The other side is not connected to anything. It took about 45 minutes to install the entire unit, another half hour or so to adjust the timing. That was in the summer of 2011 and I have not touched anything since because it has been absolutely flawless. When warm I have a perfectly smooth idle at about 800 RPM, and smooth acceleration.
If you have any issues with your distributor, however, such as worn bearings or something similar, no add-on system will solve your problems. You will either need to get your distributor repaired, or replace everything with the 123.