Does old ignition need removed if I have the MSD SCI ignition?

does my car have an old ignition that needs removed with my SCI igntion?

all you have to do is get an external coil with your sci, Like a blaster 2 coil. then get an MSD distributor cap. After that just remove the coil from inside the distributor and wire the SCI Ignition to the wires from the old coil. then wire up the SCI ignition box to the new external coil. I may have forgot something, but it is pretty simple.

Does adding MSD ignition give more HP