So this head mechanic is also a well-respected and proven tuner? Somehow I doubt that..
Firstly, there is software to tune the Blackwood ECU, available overseas and for some time. It's the same ECU as used in the European Mondeo and Focus. It will need to be adapted to the BA, (assuming that Ford Aus hasn't done this already), so that is hardly what one could consider as "NEVER be cracked".
Secondly, to put his finger on a particular figure as being THE LIMIT, is just plain silly. Has he tuned several turbos that have hit this so-called "limit", or is he talking from "I think" experience?
So basically what I'm saying is don't believe everything you hear. Until there is SUBSTANTIAL and WIDELY PROVEN evidence, then his claims have NO foundation.
I'm not even going to speculate on the maximum power issue, as I'm not qualified as a proven tuner! And anyway, I'd be more concerned with the maximum gearbox lifespan first...