I own a 2006 and the car was a mess to try to put a system in. The MostNet (fiber optic) causes a ton of headaches and either results in a lot of work or a big bill. I decided to for-go putting a new headunit in, i really wanted a Pioneer Z2, because i didn't want to run a parallel system do to the money neccesary to do it. But i did replace the front 6 1/2 with Alpine Comps added a JLw1 sub and went with an Alpine MRP-F550 amp to power it. Right now i'm just using ine out converters to gain a single from the factory amps but once the holiday OT really kicks in i'm going to add a JL clean sweep to clean up the single and replace the factory 4" rears with 6x9's.
For how great of a car the 9-3 is the system really does ****. I hadn't paid any attention to car audio for about 5 years but when i got my Saab i needed to upgrade. I'm interested to see what else any Saab owners have done.