I just bought '97 S320 with 109K dealer serviced and I have all records
Here are a few based on this car and forum based knowledge.

1) Headgasket - Has it been replaced already. If not it probably eventually will fail.

2) Wiring Harness should not be a problem

3) Blower Motor Regulator - common failure, replaced on mine

4) MAS Air Meter - Replaced on my car at 70K

5) Rear Window regulators failed multiple times

6) Outside mirrors - both had been replaced

7) You would want to know whether the Evaporator had ever been replaced.

8) Check to verify that proper MB coolant has been used, not the green stuff.

9) Lower control arm bushings - Mine were shot and had them replaced.

10) My car has several repair tickets for issues with trunk latch. The vacuum assist door closing system has never failed, but they replaced the latch and adjusted the trunk several times.

11) I would also want to know whether the transmission fluid had ever been changed.

Other than that, I would say that it would be a normal Pre-Purchase Inspection.

Steve
'97S320
'92 300E Sportline