A lot of misconceptions out there regarding boost and headgaskets.
High boost on a motor with stock heads and cam is less stressful on the motor than high boost on a motor with ported heads and cam. The problem with high boost is the high temperatures associated with them regardless of engine mods. If you have a big enough IC you can run as much boost as you want (more or less). Until you surpass 400ftlbs torque you really haven't generated enough pressure to be dangerous to a stock type headgasket. Since no internally stock SC is going to surpass 400ftlbs, it is pretty safe to say that boost pressure isn't going to kill the headgaskets in a stock SC.
What kills the headgaskets in a stock SC is detonation. In stock form and being 10-15 years old, any SC runs a big chance of being badly out of tune. Adding mods to it generally makes that condition much worse and often without and knowledge of the owner. Then add high temps from high boost through an inadequate IC and you have a recipe for guaranteed blown headgaskets.
Anyone who has upgraded their supercharger but not replaced their headgaskets can be pretty much assured they will be doing so shortly. Almost all SC headgaskets are faulty. Not all are leaking, but all OE gaskets are damaged in one way or another. The notion that you can do "this" or "that" to extend their life is a silly notion. If you have replaced your gaskets and are still having troubles, then you have tuning issues and/or cooling problems that need to be addressed. It's really that simple.
Stock replacement Felpro gaskets are sufficient for over 400ftlbs torque and 400rwhp AND 18-19psi boost if the car is tuned properly. It's not magic.
That being said it is highly advisable that with a stock IC you keep boost levels under 15psi.
David