Sounds good to me, and as long as it's unrestorable, go for it! I'm a big SAAB fan (as you can see by the avatar) so I'll be watching closely.
If you're going to be driving the project in the mean time, go for a front air dam as soon as possible.
As you know, the 99 was based on Wunibald Kamm's principles and offers a sharp break at the rear to cleanly separate flow- much like the Chevy Volt/Vauxhall Ampera are doing now. I wonder if you could make one of those on the 96 that would follow the curves of the body, but with a sharp break at the rear.
First, tuft test it and see where you need to begin on the rear end. MetroMPG has a thread on DIY tuft testing- it's really easy
