[JayChicago]

I think what 40cpe was meaning is the voltage as the coil discharges will rise until it jumps the spark plug gap. (I guess this is instantaneous, you would need a scope to see it rise) Any excess voltage put out by the coil will immediately go to ground across the plug gap, so shouldn't be a problem.

But as you point out, the spark plug is not always the point of least resistance. As you point out, too much voltage jumping the gap can cook the plugs; if you use a plug capable of withstanding the excess voltage, it will find an easier path to ground on these systems not designed for that high voltage.