^ Welcome aboard. I highly recommend using the Search function if you haven't tried it already. A quick search on 'Borla' brings up a number of results, including the following:
370Z Borla Exhaust Development
Looks like a developer from Borla chimes in on that thread. Although I don't think he gave an exact date. Still, that thread would be the place for your inquiry, as this particular thread isn't Borla-specific. If that developer is watching that thread (which I hope he is), your question might get a reply from him there.