W123 1980 300D non turbo.

First time Mercedes diesel owner, not a guru.

I am considering trying to source all the parts for a auto to manual swap someday.

I have the 4 speed auto with the red(unobtainium)modulator valve so I know one day I will have to do something...

So the parts I know that I will need are:

1: a gearbox, most likely 4 speed. Done
2: clutch plate/pressure plate
3: shifter assembly/shift linkage Done
4: clutch pedal assembly Done
5: modified driveshaft.
6: modified transmission mount
7: pilot bearing
8: manual motor flywheel Done

what else do I need in addition to all of this?

what is the differences between the one piece aluminum transmissions and the two piece aluminum/cast iron transmission?

also do you have to change the adapter plate between the block and transmission?
I have not really found a conclusive answer to this in the forums.