The VIN should begin with WDBCA42 or 43. If the 5th position has an A, it's a gasser; if it's a B, it's a Diesel. Don't put too much stock in what some lackey keyed into an on-line system. You might get a vehicle master inquiry (VMI) from any MB dealer and have them check that the VIN belongs to the car.

You can get an owner's manual from MB for something like $10. Some claim to have gotten complimentary copies. You can also check eBay. If you get the MB repair and maintenance CD set for that car (the one published by MB and available through the FastLane link at the top of this page), there's an owner's manual in PDF form in one of the CDs.

Door locks could be a bad switch in the door handle assembly. You'll need a wiring diagram to diagnose the problem.

Seat adjustment could be dirty switch contacts. Spray contact cleaner (e.g., Caig Deoxit) into the switch.

It's a day late and a dollar short but find a reputable independent MB shop and pay $100-150 for a prepurchase inspection. That will tell you where you stand and what needs immediate attention.

Sixto
95 S420
87 300SDL