for those that wonder why its the same unit;
the changes between the series 1 and series 2 RB25 are done on the engine side
that is, not on the ecu side, so the difference in coils, tps, afm etc etc are engine side
so regardless of ecu used (s1 or s2) its all the same
the series 2 coil setup is different, but its changed locally on the engine side so the remote "ecu" side is the same if that makes sense
much like the afm setup, they run different airflow meters, but its local wiring on the "engine" side thats changed around, on the ecu side its the same
ie: the pinout on the ecu side is the same and so to is the ramp, load, voltage scale etc
but there are differences on the map layer for the s1 and s2 ecu's
i tried a series 1 remapped ecu on my s2 skyline and it ran like poo
it felt like i was driving through mud