Hey Rog,
I'm not looking to tic off MSD, (as they want to sell their product). Nor do I want to steal the wind from your sails, however the theory of MSD and the multiple spark is best suited for intake systems that are poor at atomizing fuel. An engine with fuel injection is superior to a carb for many reasons, but the biggest is the fact that the fuel is atomized so well directly out of the injector. Then further tumbled and mixed with the rushing of incoming air.
The point I want to make is that for most modern engines MSD is simply not worth the money. The ignition voltage thresholds of most ignition systems built since 1990 are more than adequate for any street engine.
I encounter many a car enthusiast that spend money on cool sounding things for their car or truck and are constantly chasing nagging problems.
Please let me be clear, not everything is bad or wrong to put on one's ride....it just may be ...unnecessary.
Again this is just my opinion...but save the money on MSD and use it for something that the engine truly can benefit from.