Indeed assuming automatic to manual conversion...

You will need

1) A flywheel and a clutch pack
2) Hydraulic lines for the clutch and either a brake fluid reservoir with a supply for the clutch (as in the way Mercedes did it) or a separate custom solution
3) A different propshaft - ideally with the vibration damper Mercedes added for manual gearboxes
4) A longer speedo cable
5) A different cross member for the transmission mount - possibly a different transmission mount if your old one for the auto transmission is dead
6) Shifter rods
7) Shifter with a different bit of wood trim (automatic shifter size is different) that fits the switches etc you already have
8) Pedals
9) Clutch master cylinder and linkage to pedal

That's about it I think

Good luck finding the correct flywheel in the US of A if you happen to be there

__________________
1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!