Marty, I've been a ASE Master tech for 25 years, owned my own emissions repair specialty shop for 6 years with my own chassis dyno. When the L1 test was devised, there were 1400 techs nationwide that took it 200 passed, myself being one of the original who passed. Won Colorado's Top tech award in 1997, speaker at the national clean air conference in 97'.
Big Jim probably has more real world auto repair than anyone on this board.

Don't lecture anyone about spark and ignition theory.

I've run dyno passes for manufactures of hi performance parts, oil additives and gas additives. from Superchargers to twin turbo kits. I've done dyno tuning on jeeps to roundy racer to Ice racing jeeps.

The point of all of this has nothing to do with one coil or one type of module making some small improvment.
Results can vary too greatly to know if any of the A/M parts do anything.

What it is about is one fellow asking if spending a grip of cash on a ignition system alone will pay for itself in MPG or HP? Then find out that it made no change to a good running engine and only accomplished his wallet being lighter.

Hi Po parts have a place, however, never on a stock engine.

SD