Community members list the Buick Regal among the ordinary sedans they expect to see filling out GTA 6 traffic. In real life the Regal is a sensible mid-size car that trades sharp handling for a smooth, quiet ride. Rockstar has not confirmed any Regal look-alike, and there is no official in-game name for it.
You cannot unlock this right now because it is unconfirmed and has no in-game name. The pick reflects fan expectations for common street cars rather than any leak. If a Regal-style sedan appears, expect it to behave like a soft, everyday family car that is easy to drive and nothing special in a chase.
The community companion for Grand Theft Auto VI. Database, maps, guides and tools for Vice City and the state of Leonida.