Alternator.
Valve seals.
I really like this car. Mercedes builds them like a tank.
I honestly feel the longevity of the motor is questionable though. Mine uses about a quart of oil every 400 miles, which seems to be quite common for these older diesels.
Fuel mileage is fantastic at about 28-32 mpg from the 4 speed manual transmission. The transmission could certainly have been equipped with a much higher 4 gear. The engine spins very fast, even cruising at 55 mph.
Yes, you're right about the gearing. I have a UK 240d 5 speed, and even that sounds a bit busy at 80mph. I seem to get 38-40 mpg average though, so the extra gear must help.
The five speed box is very sought after in the US. I knew a guy who paid many thousands of dollars for one.