I recently replaced my SC gasket on my 1993 SSEI and I noticed a world of a difference. I recommend everyone to do this, and while your at, drain your SC oil and replace it. In the long run it will pay off. $20 Canadian for the gasket, and $22 for two bottles of supercharger oil. My boost actually stays a lot higher now!!
I have replaced quite a few charger gaskets that were blown out. The ones I've done were because of lower intake gaskets leaking, but when I get the charger off I noticed the gasket is sometimes blown. I would say 1 in every 5, maybe 1 in 4, have been blown.
Maybe I live in some part of the world that has a strange magnetic field though and causes premature failure of Bonneville parts cause I seem to be the only one who sees these problems.