RedCSX1, your idea of acceptable rusting is probably not what my distributor looked like after two years. I was completely shocked at what I found when I pulled the cap. MSD blamed it on a non vented cap and excessive plug gap.
I replaced the distributor and had the carbon button fail, twice, MSD blamed that on a possible crack in the button from shipment or excessive spark plug gap. I cut away my old cap and took this picture with a new rotor installed. This gap is much bigger than my plug gap and most likely the cause of the ozone production. What does not show up here is that the rotor is also lower than the post. The carbon button is making very good contact with the rotor
I am convinced that MSD is trying to ignore a big problem, class action suit is not out of the question as far as I am concerned.