Sorry to hear this Martin. This is a very familiar story......it seems that 147 GTA's are more prone than the GT or the 156. Most do seem to let go at around your mileage, mine went at just over 40,000. Unfortunately, there is often little notice of the impending failure. I was lucky in as much as my diff didn't shatter the gearbox casing. The Q2 makes a significant difference to how you car puts it's power through the wheels....and it is designed differently to the original diff, AFAIK, so it is far less likey to break..I haven't read of any Q2 failures. As long as the gearbox oil is kept topped up and the right oil is used, it should give no mechanical issues, although some people, including myself, have suffered from the odd noise being made when the system is working.
Good luck with the repair.