I have a feeling that PD are waiting for the 2014 season to start before releasing these cars. With the addition of Volvo this year and the liveries of the other 4 makes having only been hinted at, this would make sense!
Unfortunately, there is the chance that they won't make it at all and PD will only add the cars that take part in the Bathurst 12hr race...
However, with Nissan being a part of the Australian V8 series, they would be committing advertising suicide if the V8's weren't added!