If they both have service records I think you should be ok no matter what. As far as the 10k oil change. Of course yes, this is in spec, but we all know that 10k oil changes are not the best idea, and that in the case of these saabs, sludge issues seemed to happen to people doing this that lived in colder parts of the US and canada. Being that you are in VA/DC and that the 10k only happened once, I doubt you will have a problem. I think most of the sludge issues happened in the northern US and canada because of the extremely cold temps at times, combined with a lot of stop and go driving.
As far as what oil to use, if it was serviced at the dealer it was most likely mobile1 full synthetic 5w30. In my case, I speculate it was on semi before I got it, but I could be wrong, it could have been full. The thing is the previous oil filter was not a saab filter, and looked like something used by an oil change shop or something, so who knows what they put in it, so I just assume the worst.
If you will be doing your own oil changes and have a membership to BJ's wholesale or some other type of wholesale club, I highly suggest you check it out. I am able to pick up 6 quarts of mobile1 full synth 5w30 for $25. Most other stores it's about $6 a quart. A lot of people here will recommend 0w40 or something like that, which is great, but the problem is in my area it's hard to find anything other than 10w40 or 5w30. In the summer I just change my oil more frequently and stay with 5w30. I may start doing 10w40 in the summer and 5w30 in the winter, not sure yet. Although I for sure cannot find any 0w40 in my area, I think that is mostly found in the northern US and canada.
Either way I think you will be happy, and with full service records you should be fine. Although getting an extended warranty with the credit union if you get the '02 may not be a bad idea. Also, if you don't mind me asking, what is the price difference between the cars? Before you decide though, just remember to check everything out thoroughly. Even the little things like the stereo and cd player. Even if the air is on, check the windows, check the sunroof, etc. I know sometimes if someone is in the car with you, its hard to remember to do these things. Also one thing I always check is under to trunk liner to make sure there was no water damage, the last thing you want is a leaky car. I have owned a lot of hatchbacks/5doors and a lot of times they can develop leaks into the trunk, especially if the car was in a minor accident that was never reported and a panel was replaced.
Enjoy!