They are from the PROCAR series. Nations Cup ran the sportscars like Lambo, Ferrari and Porsche. GT Performance ran cars like the Imprezas, Evos, Golf R32 and the higher performing V8s from Holden and Ford. The Australian Production Car Championship (APCC) ran everything from Mitsubishi Mirages and Celicas to MR2s, BMWs and the more 'family' cars like Magnas, Camrys 6cyl and 8cyl Falcons and Commodores.
If you check out the PROCAR thread you will see that most of these cars have nowhere to race next year. Hopefully it will be sorted out soon.