Which Saab 9-3 Aero? The T5/T7 engine ones from 1999 - 2003? OR the T8 sports saloon from 2003 onwards?
The later ones had a better chasis, strong brakes and good engines... they map about the same as the GTI to around 240-250bhp on a stage 1; standard clutch seems to start slipping around the 300lb/ft mark though.
Heavier than the GTI, iirc ~1490KG.
Things to look out for include signs of snapped front springs (very common) - some interior plastics very cheap, thank GM for killing the brand.