If memory serves the 89-92 engines have forged internals (or pistons) don't they.
What's the CR?
I was thinking stock Notch M5 with 3.73 gears and a catback with a 2.2 KB @ 9psi or so (more if possible). What do you guys reckon to that as a simple setup and what sort of rwhp do you think it would produce.
Forged internals or not, it is the head gasket that is the issue. Over 9 or 10 psi and a worn stocker gasket is gone based on in depth reading.
Once over 10 psi, internals become an issue too. Even if they are forged, if the engine has not been rebuilt, seals are not going to be great and problems will pop up.
You'll be fine as long as you keep the detonation away. I've seen a stock block handle 18psi all day long. But the stock block can't handle much more than 500HP and be expected to live, they crack down the middle.
A bone stock motor will produce around 190-215 FWHP depending on the miles and condition. with 9psi you'll have from 290~330 FWHP, 12 will give you around 325~365. 18 will put you around 390-440. But this is using the formula off procharger.com. Your specific supercharger may give more or less depending on its efficiency.
Keep in mind, some sort of fuel system upgrade will likely be in order. And I'd run cranking compression and leak down tests on all cylinders before I started cranking the boost to it. A new set of head gaskets designed for boost (Cometic) and a set of ARP studs would be good insurance that all that cylinder pressure pushes on the piston.
The switch to hypereutectic pistons occurred late in the 92 model year - around the last 2 months of production. So it's possible if you have a late-build 92 that it has hypers, not forged, pistons in it.