For the suspension, you have a few options. I would recommend the SAS 9Swedish Auto Specialists) sway bar kit which is thicker than stock and really sharpens up steering and improves cornering stability. You could also go with Bilstein struts and shocks for a stiffer ride. If you want to lower the car, there are a number of spring options including Intrax and H&R. Every 9000 I've lowered has had slight rubbing issues with any wheels wider than 7", so be mindful that a low car may limit your wheel options.
As far as I know, all 9000 turbo brake calipers and rotors were the same '88-'98. Those years had ABS, so I'm not which components would be compatible of if they'd really be an upgrade at all. I know "big brake kits" are available for the later 9000s, but I do not know about the 1986-1987s. Maybe someone else on here does.
You could go with EBC Red Stuff brake pads for more braking power using your current setup. I have drilled or slotted rotors on a few of my cars and I like them, but others say they're just for looks. My 9000 is extremely fast and I've always found the stock brakes with good pads are more than adequate. My recommendation is to get some good brake pads and sticky tires. A car can only stop as quickly as its tires will allow.
Thanks for the replies! I'm unsure if it is a Carlsson kit or not, but it does have the Saab airflow badge. Super neat car and very well taken care of. Two rust spots of rust the size of toothpick ends. This is its first winter, and it's going in for undercoating on Friday.
As for performance, Sway bars and suspension are on order.
If all 9000 brakes are compatible, which of those years have a larger caliper/brake pad? And are 9-5 Aero calipers an upgrade on 9000s?
9k aero brakes, and normal 9000 brakes are the same during the later years, just using high quality pads/rotors with the later calipers will provide a good upgrade.
if you are looking for power, you options are pretty open, Newer 9k drivetrains/subframes bolt right into the older bodies, so if you are willing to put the work in, one good parts car can make a huge difference
also converting them to t5 is a breeze, since unlike c900s you can pull a junkyard harness that is already made to fit in that body (IE all wires are in the right spot already)
play your cars right, and you could have a super badass old body 9k for not much more than the cost of a parts car, and normal refresh parts on the way in.