Welcome to the forum from Atlanta! Start with the transmission, it should shift smoothly and cause no check engine light....there should not be a shift upward arrow on the dash either. The fluid should be pink to red and not brown, or worse, black, and there shouldn't be any burnt smell to the fluid. If you encounter this, you might question if the transmission is going to last....cared for correctly- a transmission flush before this condition and then routinely every 30-40K miles will be exactly as you said, good maintenance to see that the car drives well into the 200k's. A transmission replacement on these cars can run you well into the high teens and possibly even 2grand, so check it out carefully. Also, the engine is important, but pretty sturdy on these unless the timing belt has snapped, or has jumped a tooth or so (you'll notice a rough idle and possibly missing) or the head gasket was compromised when the car lost coolant and over-heated. Check for signs of this...white exhaust and green fluid under the car. Otherwise, the engines and the turbo's are very stout. Another issues revolve around an uncared for PCV system which creates positive pressure in the crankcase causing the rear main engine seal to leak...this is expensive to repair as the engine has to be dropped out of the car with the transmission, the two split in half and the new seal installed....a grand or more. Finally, the weak link in the 850 and first 70 series cars is the A/C evaporator...when it leaks, you don't have cold air at all..you can add gas but very soon it leaks out again. The only solution is to take the entire dash out of the car and replace the evaporator and other components. At the dealer, this carries a $1600 price tag. So, I've listed the main things...the things that would keep you from driving the car on a long trip...and things you should be careful of. Suspension, tires, brakes, etc. are general maintenance items and certainly should be checked out but aren't that difficult for any mechanic to do and shouldn't cost you an arm or a leg.