312 motor wont work with your current Microtec ECU, you will need the complete loom from a 312 with its ECU!!
I have a 910 motor in my 750, even though on paper the power difference is small, in real life you cant compare them, the 910 engine will walk over the 750 engine in every aspect.....
No you don't. The M232 that i use to replace the 16M ecu allows conversion to sequential injection. Data is data so we can copy that across and fill in any fields that differ slightly. Sensor calibrations are the same.
You can do this conversion with only the addition of 2 parts. Throttle bodies for injector size and exhaust system due to potentially taller engine. The only part you'll not be able to run on the conversion will be the EBS system as the std wiring loom has no facility for it, the 1000S does though so you could upgrade a 1000S fully to 312 spec.