ballast resistor

hey guys, i have been installing my ez wiring aftermarket harness and i noticed they dont show to wire in the ballast resistor with the old points style ignition. but in the electronic ignition section they show it. i am running a pertronix ignition kit and it shows to still use the ballast resistor. so i am a little confused. i am going to give them a call tomorrow, but i just thought someone may have run into this before.