No belt likely means the compressor has been sitting for a while. Expect major AC service to recitfy. Lots you can do yourself. Stay with R12 for best performance especially if 110*F is common where you'll be driving.

Lots of info in the archives around rough idle. Prime suspects are dirty fuel system and need of a revised rack damper pin.

How can AC be on max with any effect if there's no belt on the compressor? Or do you mean one of two belts was missing?

Hmm... these engines are known for off-the-line torque compared to other MB passenger car Diesels. Could be the fuel system needs cleaning. Could also be an impeded boost signal to the injection pump. Typically a worn turbo will mean lazy acceleration all the way, not just from a standing start.

MB tex, which is vinyl, has the appearance of leather. If the pleats go all the way to the forward horizontal edge of the seat, that's MB tex. Seats with leather upholstery have a solid swatch across the forward horizontal edge of the seat. Leather is very common in these cars so no reason to doubt it's leather. MB tex is a lot more durable.

The rear window probably needs a $10 part and an hour of your time.

$4500 seems high at first glance but if it's a keeper with little more than the problems you noted then what's a few bucks? All MBs basically cost the same. You can pay for it up front or pay over time. To me the determinant would be maintenance records. If it has a good documented history then $4500 for a car with 138K miles is a bargain.

It's rare that an MB of this vintage doesn't need $1200-1500 worth of front suspension rejuvenation. If the records show that suspension work was done recently, wonderful! If not, I doubt the best maintenance regimen can prevent wear. Most rear suspension rejuventation can be handled by a DIYer. So with front end work with a few special tools but I'd rather remove and replace transmissions repeatedly for the same amount of time that it takes to work on the front suspension.

Sixto
93 300SD