 In late 
2005, test mules were also spotted on the Nürburgring that were made using body panels from Toyota Crown Royals that were shortened by cutting out sections of the roof and rear doors.The winning exterior design proposal by Hiroshi Okamato (supervised by chief IS designer Kengo Matsumoto), was finalized in 2005.On 6 December 2006, Lexus officially confirmed the existence of the vehicle which they called IS F in the press release.