A copy of the ECU wiring for MEMS1.9 and MEMS3 cars with a pinout diagram for the MEMS3 ECU plugs with my pencil notes on colours to help you in your conversion.
If you are not fitting a MEMS3 engine into your car you will need to swap the following MEMS3 items to the existing MEMS1.9 engine:
Alternator, cam cover and twin coil packs, inlet manifold and plenum with sensors, probably the crank sensor too, since later ones have a different part number, coolant temperature sensor, engine wiring loom, ECU and 5as set with keyfobs, engine relay pack is not a necessity but it saves some faff, although it is not a straight forward plug in I don't believe. O2 sensor, or cut off and swap the plug... MIL eliminator kit if you plan to add a MIL light in somewhere, but the light is not a necessity. The ZnF remap switches the second O2 sensor not present error off anyway. Its worthwile swapping out the exhaust manifold and flexi section for a six bolt version too. You will need to upgrade the permenant live feed to the ECU as the old MEMS1.9 permenant feed isn't up to the job since the MEMS3 ECU powers the O2 sensor heaters, whereas the old 1.9 version uses the engine bay relay pack. (Took me three days to figure that out)
Ignore the rough road sensor, it is not needed. If you fit a coolant level sensor, use the old cat overheat feed from the ECU plug to light up the light on the dashboard... OEM looking.
MEMS1.9
MEMS3
Hopefully this will help.