Formula One car development blog
Williams' changed brake ducts

As a final update on their FW32, Williams have introduced new brake ducts for both the front and rear brakes. The new ducts feature a shield to prevent airflow into the duct to be disturbed by the rotating front wheel. This design feature is far from new and teams like Renault or McLaren have been running it since the beginning of the season.
It is however likely that Williams have now changed the front brake ducts to better work with the new front wing they introduced in Singapore. While the endplate on that wing has become simpler, the stacked element hangs over the endplate for additional downforce. On the inside, an extra small stabiliser element was added as well, while the black flaps closest to the front wing supports are now similar to Renault's solution.
Williams move forward with blown rear end

Williams have introduced yet another major car update at Silverstone after introducing an effective F-duct at the previous Grand Prix, held at Valencia. The car already showed much improved pace in Spain, but at Silverstone both drivers could confirm their performances thanks to a new blown diffuser.
The change will obviously benefit the FW32 a lot as it previously featured high exhausts that appeared to disturb upper sidepod airflow quite a lot. The new sidepod slopes down much steeper, resembling much the design of the Red Bull. With this change, exhaust gases are now pushed onto the diffuser, allowing it to work more efficiently while drag will certainly have reduced above the sidepod.