No offence Ian, but I am surprised people are even asking for technical details on something that doesn't exist (to the public) yet. Wait until mid / late 2013 when the 2014 models hit the streets. Like I'd said in an earlier post, I am amazed people are sending me PM's asking will it be supported, well, I checked my tarot cards and there's nothing in them that would indicate what it is. I think the thing to keep in mind is until we get our hands on one I will stick with the theory that most of what you read will be BS. Like this 'uncrackable' speculation, as Howard had said, we hope that GM realises that if they do make this ECM untunable then sales of GM V8 vehicles will fall.
Take for example the LML ECM (Bosch EDC17), sure we can't read them, but they can be flashed via the OBD-II port still, whereas many European cars with the EDC17 cannot, they must be pulled apart and flashed via the debug ports (though I hear that can't be done on the newer ones either). GM could have asked Bosch for that option surely?