I'm giving advice on what I do now and that is I went from a factory ignition with ballast resistor and everything to full MSD and did not pick up or drop anytime on my time slip... Others results may differ but this is my experience...
Real world at the racetrack...
I know. I use a factory ignition too, with GREAT success, but 1). The OP didn't ask about factory ignition and 2). I'm getting tired of arguing in favor of it when people don't listen so I'm ALL FOR whatever he wants to do, he just needs to verify.