Change all fluids, number one. Especially the tranny.
If the transmission is shifting funny, check it out -- do the band adjustment (plenty on the board - just search on "band adjustment" with the quotes). At 85K, the auto should be pretty good, just high revs at highway speeds.
Clean up the ground points, those tend to corrode a bit and cause some funky electrical issues.
Since it is a convertible, I would check the converible top fluid and rams (under the back seat) if the top is making a lot of noise. If it isn't, you're good.
Most of the other stuff is really accessories -- your cruise may not work, A/C may be dead, the light switch may spin in the dash, the dash is probably a little cracked, seats may not sit straight or adjust properly and the trunk probably smells like gas. Join the club!
Oh, and check the information in the Tech.Help section here, look at
http://www.twinsaabs.com,
http://www.900aero.com, and
http://www.townsendimports.com.
Get the Bentley shop manual for 16-valve 900.
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