Compulsory Third Party (CTP - Suncorp in your case) only cover the PEOPLE you hit in accident. Third Party Cover (RACQ) cover their cars and properties. e.g. If you hit a Porsche today and the Porsche driver is injury, Suncorp CTP will pay for the injury of Porsche's driver but without RACQ you will have to pay for the repair of the Porsche.