Cloudee: Simulators and derated performance didn't exist then. It's comparing apples and oranges. Regardless, the RAAF doesn't own any CT-4's (bar 77 at the RAAF Musuem). They're owned and operated by BAE systems, contracted for RAAF use.
The chances of finding ex RAAF PC-9''s at auction will be, from what I understand, slim to nill. Always happy to be wrong.
Frankly, with serviceability being what it has been, I don't know why you'd want one.