Please can anyone help he withe the following.

I currently have a e46 318 ci with auto transmission, i have been offered a 320 e46 engine and manual gear box.

How easy is it to replace the engine and box? (I have had experience in engine rebuilds and replacements)
will I have to replace the engine wiring loom and ecu?
will I have to replace the drive shaft?

Anything else i need to know?

any help would be greatly appreciated

Many thanks