The chips for the motronic can be swapped. The older boxes can be easily updated to take the later chips. ROW did not have oxygen sensor. I had a euro harness and US box when I purchased my 3.2 for swap into my 1973. I added the oxygen sensor wiring to it. I have read one of the best factory chips was for the Club Sport.
Steve W did a review of the different chips.
Carrera 3.2 Performance mystery and Chips (long) - Rennlist Discussion Forums