I am faced with possibly rebuilding the transmission in my '92 300D 2.5 (602 5cyl; 236k miles) in the near future. As an alternative, I am considering buying a parts car with moderate mileage. I found an '87 300D 3.0 (603 6cyl; 127k miles) with damage to the driver-side doors (thus quite cheap). Is it possible to outfit my '92 with the transmission from this '87?

The driveshaft output flange and cooler lines are different sizes, and the NSS uses a different electrical connector. Once you get past that it'll work.