The design of the 2003 Williams FW25 was a marked departure over its predecessor, and was a completely new design compared to the Williams FW24, something that Williams had not done between 2001 and 2002.
The 2003 Williams FW25 design was a significant change from its predecessor, being entirely different from the Williams FW24.  This marked a departure from Williams' usual pattern of not creating fresh designs between 2001 and 2002.