Thanks guys, it starting to make sense now.

Regarding the coil.
I previously stated:
Left = ?
midle = ground
Right = 12volt

This because i had a pin on the inboard 37pin multiplug on the engineloom that went to the right side of the coil, but now i also see that ECU19 goes to this pin as well.
So this means that this pin is intended to connect the tachometer right?
I can use signals from the right side of the coil for this?
Any reason why they get the tacho readings directly from the coil instead of a separate tachodrive output channel?

So how it really is is like this:
Left = ECU55
midle = 12volts
Right = ECU19 + pin39 on multiplug for tacho reading