A few things.

Other than checking mileage, ignore Car fax, it means nothing. Have the car inspected by a MB dealer. There is no substitute for an actual inspection by a shop.

If someone crashed the car and paid cash to fix, it won't always show up. And if something does show up, it can be wildly overstated. My 97 SL320 is car faxed with "Moderate rear damage" sometime prior to me getting it. The rear damage was a replaced rear bumper cover and a very shallow dent in the bottom of the spare tire well that I more or less pushed out by hand. I'd hardly call backing into the lawn mower moderate damage.

When I removed the front bumper cover to repair a tear, I found it had been repaired / painted 2X for minor bumps that never showed up on CF. ( Original paint + 2 more layers )

I don't know these year cars specifically but I don't think much if anything changed from 98 / 99. Google "Ken Rockwell Mercedes SL " He has lots of pics and a bit of yearly "whats changed" He is more a photographer that a car guy so some of the car info may be suspect. ( RE: listing the 63 Chevy Impala as the first 4 door "Coupe" The End of Mercedes when this was really called a "pillarless hard top" or just "hard top". I still have Moms 1956 Plymouth that is a 4 dr hardtop so that even predates the Chevy. )

Regardless of the car, giving it a preemptive reconditioning will reduce the number of random breakdowns. I change parts when they get towards the end of expected life not after they fail.

With nearly 100 K and 19 years, I'd expect to change: brake hoses , all coolant hoses , fan belt, spark plugs / wires / boots , filters , fuel pump , drive shaft discs for starters. Remove the front hubs and repack the bearings ( or just change them as they are cheap and you'd pay more in cleaning / inspection )

Lower ball joints on these cars tend to rust / lockup when the rubber boot fails so I'd have a look there. ( not expensive to change )

Upper strut mounts fail, but are not expensive to replace. ( If the car has self leveling / active shocks, the upper mounts are different and may be more $ )

Transmission shift bushings ( 2 of then ) come apart making for a floppy shifter, the parts cost almost nothing.

Transmission connector bushing / plug leaks internally and fluid wicks up the wires to the trans computer. This is cheap to fix.

Washer bottle pump grommet shrinks / leaks , parts cost almost nothing.

If you change the wiper blade, just get one from MB, the aftermarkets ones I've tried don't fit and the MB one was actually less $.

Now for the expensive stuff that more or less is let go until it fails:

The AC evaporator / heater core. This is a major dash out operation that is $$$$. I think the factory calls for 40 Hr labor.

Hard top / soft top hydraulic cylinders will end up leaking on ALL cars at this point regardless of mileage. If one is leaking the others will be in a short time. Buying new cylinders is big $ ( there are 11 to 12 of them depending on the year ) but replacement seals can be had from aftermarket vendors. Changing the seal isn't difficult, removing the cylinders is the time consuming part.

My system leaks but I leave my hard top on year round so no loss there. I did take it off to inspect / resew the soft top. There is a manual operation procedure that is simple so it isn't worth my time to fix the leaks.