[1] In the first era the championship races were open to closed roof cars (not necessarily production based) complying with CAMS Appendix K regulations.

The category was something of a hybrid with European racing cars, American IMSA racers and wide variety of Australian Sports Sedans competing together.

As with Appendix K of the 1960s, grids were widely varied with turbocharged Porsche 935s, BMW 318is, 5.0 and 6.0 litre V8 powered Chevrolet Monzas, Holden Commodores, Alfa Romeo Alfettas, Thomson's lone Mercedes-Benz 450 SLC, Peter Fitzgerald's non-turbo Porsche Carrera RSR, a couple of V12 Jaguar XJS' and with a variety of sports sedans such as the Holden Monaro and Holden Torana, Ford Falcon and Ford Escort, and various turbocharged Toyotas, Nissans and Mazda RX-7s.

Veteran driver Kevin Bartlett introduced a very quick Ground effects De Tomaso Pantera in 1985 which brought some much needed spice to the GT category.

Most of the competing 2004 cars remained eligible for 2005, although the controversial Holden Monaro 427C's which had won the two Bathurst 24 Hour races in 2002 and 2003 were a notable exception.

Manufacturers have diversified widely from its mostly Porsche base and in addition to the 12 Hour has also seen the creation of other long-distance races, the Phillip Island 101 and the Highlands 101 in New Zealand.

In 2020, Australian Racing Group and SRO Motorsports Group jointly took over management of the category, renamed it "GT World Challenge Australia" in alignment with their other SRO GT3 categories around the world, and ran events as part of the ARG-run SpeedSeries event series.

[2] In 2024, the main World Challenge category became exclusively for SRO GT3 spec cars, with a separate set of races for GT4 known as GT4 Australia.