1981 300SD

So I've decided to pull a trans from the local pull a part junk yard.

Its unlikely that there will be a 1981 300SD, but fairly likely that there will be a car with compatible trans thats been wrecked (crashed so still moving), diesel or not.

Questions: What would be the best trans I could get for this thing from the range of 80's era Mercedes that would be compatible?

Is the 722.4 better than 722.3?

Which year should I get if there is some choice in the matter?

Would the one from a gas powered mercedes work?

Anything anyone can tell me would be appreciated.