I've been looking at different things I can get rid of, and it all comes down to comfort vs. weight reduction. Here's a short list of what I've thought about removing so far:
Seats, rear and passenger, and I think I could prolly swap out the driver's side for a lighter model if I found some compatible rails. That lumbar support thing smacks of dead weight.
Doors. The Fiat Croma has the same shape and size of door (seeing as both the Croma and 9000 were based on the same platform) but lighter. Dunno if I'm ever gonna see a Croma in a wreckers this side of the pond, but if I do I'm all over it! Croma doors don't have the same reinforcing as the 9000's, ergo way lighter.
Climate control. The blower motor, the AC system, that stupid vent adjustment motor. As well, there are vents under the seats, and these other silly fans in the rear doors.
Wheels. Saab stock cross spokes are a little lighter than the rest.
Exhaust. Swap out the steel for a lighter setup.
Fuel. Smaller tank, and say bye-bye to that auxillary fuel pump.
Glass. It's a bit finicky, and I haven't really tested it, but my theory is that pre-90 glass weighs less. If I remember right, in 90 Saab changes to a special "heat transferring" glass. I don't know for sure, but it might be a heavier type.
There are a bunch of other things, like the central locking, sunroof, SRS (airbags) that can make a small difference, but I think these are the biggies. As well, I'm sure there are things like lighter axles and driveshaft, but I don't know if I want to take things that far.
Did I forget anything?