How has this not been mentioned yet!?

The Big Steal, 1990, featuring Ben Mendolsohn, Claudia Karvan, Steve Bisley among others.

Merc W123 wagon with period roof racks.

Because domestic wagons are so mainstream...

Probably because the basic concept of the Monaro/GTO had been around since 1998, and in production since 2001. It looked pretty amazing when it was first revealed/released.