For the 113 owners : An added note to SB's correct info on the 280se 4.5 diff change.
This rear ratio is 3:27 and I have done this change-out
and must say the improvement is excellent.
Note that I have done it to a stick shift car[4speed],
but I don't know if I would try w/auto.
This can be done on all 113's [230/250/280],with the added advantage on the earlier models of up-grading to rear disc brakes. [ if swapping complete rear].
PS- Speedo will not read correct.