Where are other P2 Prototype cars? I only see the Chevrolet Daytona Prototype and Radical cars. Can not you buy it again in Raceroom?
AFAIK they are free, so no - you can't buy them. If I got it right, the free cars or content in general aren't listed in the store anymore, as it was in the past...
You can still get to their pages directly, though, for example if you want to see the specs: http://game.raceroom.com/store/cars/p2/raceroom/dmd-p21 http://game.raceroom.com/store/cars/p2/raceroom/mistral-m531