Here is another of my contrarian viewpoints.

What's always left out is that you may not have much time.
This car at that price will not be unsold for long.

I would do a CarFax to verify where the car has lived it life ( as in not in Katrina ). I would also want to verify that the mileage is legit. I would drive it. I would open the expansion tank and see whether the coolant is green.
You don't want green, you want the proper MB coolant.

I would drive it and see if you like it. Pay attention to any hesitation on acceleration from stop (defective MAF sensor $300+). Does the transmission shift smoothly. These cars are fast and come on strong from about 3,000 rpm up to redline.

Do you hear any funny exhaust sounds, as in rusted exhaust parts ( common )?

Does the A/C blow cold air? Cold air should not come out of the center vents.

Any receipts for Head Gasket or wiring harness replacement?

Pre-Purchase Inspection is very wise if practical time wise.

In my opinion it all boils down to whether you really love the car. It will cost some maintenance dollars. It will also roll on past 250K miles if properly maintained. My current '92 300E is at 244K and going strong.

Steve