No.

The differentials are identical.

The trailing arms are identical.

The space between the two is wider on the SD .

The SD has a HUGE inner can/joint on the axle.

The w123 axles actually will fit in, and function on the sd... but it will not last long.

No freaking way on earth to get SD axles into a w123.

__________________
John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 560SL convertible
1987 190D 2.5-5SPEED!!!

1987 300TD
2005 Dodge Sprinter 2500 158"WB
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!