All of those items are pretty common, especially 09's. Some time in 2011, they removed the steering lock mechanism. Also replacing the CSC with a beefier aftermarket unit would have been a better choice. Rear diff isn't worth much after 50k miles or so and acts like an open diff over time. It's crap. Did you get reimbursed for your steering lock?
BTW, I love my Z, none of those issues have crossed my path
