The Ferrari Edizioni Special Cops and the Simply Jaguar Cops pack contain Ferrari F40, Ferrari F50, Jaguar C-X75 Prototype, and Jaguar XJ220. Both the Ferrari Edizioni Pack and the Simply Jaguar Pack are also available separately in a racer package.
From what we have been able to make of it, the DLC does not include any additional racers or open up any additional areas on the map. This DLC at least seems to be restricted to just new cars. A content update checking in at about 375MB is also available for download. It is not clear what is included in this content update or when it will arrive on all of the other formats that Rivals has been released for.