I've never Seafoamed my SAAB, but did my Jeep. 1/3 on engine oil, 1/3 on fuel tank, 1/3 into engine through the vacuum hose attached to the brake booster. For the vacuum hose I let the engine sip 1/6th of the can using vacuum, then shut off engine and poured the last 1.6th can down the hose, filling it up as it took the Sea Foam. Let it sit with the liquid in the engine for 10-15 minutes, then start it, with all the glorious white smoke that Sea Foam produces. The go for a 20-30 minute drive, working the engine to redline, putting the engine through its paces.
There are plenty of You Tube videos on Sea Foam, some showing SAABs, my guess is it won't hurt your engine.
There are plenty of You Tube videos on Sea Foam, some showing SAABs, my guess is it won't hurt your engine.