96VR6NZ

Tunetechnic in Auckland did an awesome job. I sent them a spare ECU and they tuned it to our set up, the exhaust and air intake etc. They estimate an extra 15kw and 25Nm.
It goes well, the torque is there all the time and peak power gives a real kick at the top end. The auto box is in its element, its smoother and more predictable. It has transformed the car. I also reckon it's the best looking VR6 in NZ!
 

We got it sorted finally.
Replacing the immobilser control unit restored the communications at the OBD port, apparently the diagnostic connection goes through the immobilser.
The ECU was re-coded but still cranking with no start.
The coil pack was changed and she started up. No trouble codes in the ECU.
 
So to summarise, the problems were caused by three components becoming faulty at the same time. The ignition switch, the immobiliser control unit and the coil pack.
2 days labour plus parts... ouch.
 
She was going great for a day until the MAF sensor failed, but that's a different story....
 
Thanks for your ideas and suggestions guys, I learnt a lot.