The car was driven by Jacques Villeneuve and Jenson Button, the former being replaced by test driver Takuma Sato for the last race of the season.

The design was conventional in the Williams style, and the performance was improved over the 004, but issues such as a smaller gearbox, engine reliability, aerodynamic efficiency, and matching with Bridgestone tyres were still being resolved.

The 2003 season was a turning point in the relationship between Jacques Vileneuve, who had competed with the team since the beginning, and BAR, as the young talent Jenson Button showed better performance.

BAR used the 'Lucky Strike' logos, except at the French, British and United States Grands Prix, which were replaced with a barcode and random words "Look Alike" and "Don't Walk".

During the 2003-2004 offseason, BAR used the 04 Concept Car, a modified version of the 005, notably featuring a black and gray livery and the Honda RA004E engine from the following season.