Hi Liam,
Interestingly the "celebrity car" is privately owned and entered (Stillwell BMW from victoria) and is not a BMW Australia or Mini Challenge / Sherrin Motorsport car.
I guess they figured to maximise there TV exposure it would be good to get a different person in the car for each round. It is probably a pretty smart concept

They may not win the series, but I guarantee they will get plenty of TV time
Cheers
Robbo