Replacing Differential on 1984 190D 2.2

I committed to buy the 1984 190D I asked about earlier (waited too long on the 190e and it sold to someone else).

The car is in pretty nice shape--only needs a single spot of rust touchup.

A few minor repairs noted==> Driver's window doesn't work (think it might be the switch), Sunroof doesn't work--might be stuck as the motor whines but nothing happens.

Was told the mechanic said needs strut mount (found the part already), wheel bearing (ditto).

Only other major thing is the differential. I think I saw that the diesel has a 3.0x differential. I found a couple of 190E differentials (3.27, I think)--does anyone know about swapping these differentials?

Any problems on removal or re-installation that are known?

Thanks!!

AFARR