Got a 9-3 anniversary model 150hp diesel on a 57 plate. Only had it 5 months but I think the anti roll bushes are now worn...but apart from that all good. Got 65 to the gallon recently but it's not a slouch when you need to get somewhere
They can do epix mpg, but like all diesels need cleaned out.
If you drive the 1.9 150 like normal allowing it to boost lots at low rpm, expect to get mid 40s. You have to treat the throttle very gentle in order to get over 50, although once used to the sensitive pedal you'll be fine.
Who's got a Saab, is it an estate? Is it reliable?