I put the link up for the SAAB and here is my personal experience with my 03 9-5 Aero so take from it what you will.
I got our 9-5 with 100K on it 4 years ago, it now has 180K on it and it has been very reliable for me. We got it for my wife when our second child was born because her current car was too small for 2 car seats. Anyway, aside from brakes and oil we have only had 4 issues with it and none of them are very big.
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There are two plastic rollers for each of the windows. One broke on the drivers side. I replaced both from parts from the dealer and the grand total was $16.
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One side of the factory wind deflector for the sunroof popped up. I fixed that with a pop rivet.
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Now that the car is 10 years old the battery that feeds the alarm is going bad and if the outside temp gets close to 0 the alarm will go off. You can get the alarm turned off by a shop via Tech II or you can just remove the battery. So far I have removed the battery but I intend to get it turned off at some point.
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There is a wire loom that runs out of the car into the trunk lid. The wires in the loom are known to break where they flex coming out of the boddy and this happened to mine just before Christmas. As a result the trunk will not open. The fis is to send one of my children intot he trunk, pull the release and splice in new wire. This is one the list of things to do but not really that high right now.
Thats it and for a 10 year old car with 180K that I do not baby I think its been great. Mine is a 5 spd and I get mid twentys on my commute, about 26 miles with a 50/50 mix of highway and stop n-go. On highway trips I see low to mid 30's as long as I keep it around 75.
I have not found any parts hard to find and now that the Chinese are building the cars for the Chinese market things should stay that way.
The one thing to keep an eye on is the Direct Ignition Cassette. It is the COP for the car but it is one piece and if it dies you are stuck. The one on my car is at about 100K miles and has shown no signes of letting go but I am getting a spare to carry in the trunk. If the car starts throwing out miss fire codes that usually points at the DIC. It is 4 bolts to take it out so every time I change the oil I pull it off and check the plugs. Using that method I have put @ 300K miles on SAABs with DIC and have only had one failure.
As long as the oil has been changed when its supposed to with Synthetic oil you should not have any issues with sludge but it is easy to check. Take a wire coat hanger, stick it down the dipstick hole and scrape it on the bottom of the pan. If you get gook that makes the car much cheaper.
There is also a "heater bypass" hose that has a valve in it that tends to leak. You can replace that part, not expensive, or just bypass it. Again, not expensive and not complicated.
That is all I can think of right now. Mine has been the most reliable car I have had, this includes the 90 Celica and the 93 Civic I have had. I drove mine from Ohio to Arkansas and back this summer and would drive it across the contry with no resurvations.
If you have any other questions ask away. I think these are some of the most undervalued cars out there right now. They are big inside, safe, reliable (at least mine has been), fun to drive and good on gas.