Diesels take boost a lot better than gas engines bc there is no spark ignition of the fuel - it is all compression based. In a gas engine your boost is limited but pre-detonation and the strength of the engine. In diesel, as long as the fuel ratios stay correct with in increase in boost, your limiting factor is the strength of the engine. I'm a diesel mechanic, but I work on large trucks and machines, not diesel car stuff so I don't know the Saab setup at all without looking at it personally. I would definitely get into a forum and see what type of things work and don't work in your situation.