If you want to be 100% legal, buy a used physical DVD copy on eBay for $10, then apply the DODI Remastered Mod pack separately (by extracting only the mod files). However, for most users, the repack is the only way to play this remastered classic.
The gameplay in Need for Speed Carbon Remastered - DODI Repack remains largely faithful to the original. Players take on the role of Nik, a young racing prodigy who returns to his hometown of Rockport to find it overrun by street racing gangs. The game's narrative explores the world of underground racing, where players must build a reputation, gather a crew, and take down rival gangs to dominate the racing scene. Need For Speed Carbon Remastered - -DODI Repack-