I just did a 83 Malibu wagon. It was pretty simple. The C100 connector from the Malibu was exchanged with the one that the GN used. There were 4 circuits that the Malibu did not support. CCCI, ecmsol, fpinj, and fan rly. For these I installed a fusebox under the hood and used the pink HEI ignition wire to power the fuses.