the mercedes rear ends are not happy with toyota boxes, and to top the cake - I'll tell you a little note from the mercedes 124 workshop manual.
The propeller shaft is balanced - both 2 shafts, then the two yokes included, if a little mistake in assembly is done as to align the shaft one spline tooth off on either piece it will make the car shudder and drone on various speeds
then there are the rubber flex discs on the prop shaft, if they tear up (usually trans side) the outcome is disastrous - the transmission tunnel gets damaged, air bags if equipped will fire due to the shock and your transmission will deteriorate to pieces, and the prop shaft would be scrap metal.
I know for sure there are no lathe specialists in Pakistan who have a prop shaft balancing machine (cutting and welding yes - Balancing, no) - and yes I know the 2JZ transmission uses a flex disc too - but of completely different design which is not compatible with a mercedes shaft.
If you ever worked on a Benz (specially a 124) you will come to know how much thought went into designing it. Every little detail.