I have referenced this post on Renntech a few times:
https://www.renntech.org/topic/51783-boxster-dme-72-to-78-transplant/ There's a spreadsheet that shows some of the wiring differences. The body harness to the DME will need changes.
The fuel system in 2001 and earlier 986s has a fuel pressure regulator on the fuel rail and a return line to the tank. 2002 and later 986s have the regulator in the tank and only one line to the rail. [Swap fuel system from the tank to the engine or maybe swap the fuel rail from the '01 engine '03.]