Williams have dropped the controversial exhaust vane from its 2013 challenger following the FIA's ruling that it is illegal.
The FW35s vanes on the inside exits of the Coanda exhausts as well as that on Caterham's CT03 were given the thumbs down by motorsport's governing body.
The team's technical director Mike Coughlan was quick to dismiss concerns after the initial ruling, saying "ours is okay".
"If you look at ours, it's not a single piece - it's two pieces," he said.
"You're governed by total aperture size and [the need for it to be] a single aperture.
"Ours is a single aperture joined by a very small slot, so it's actually two pieces."
However, they have been forced to change their tune and have removed the controversial part.
"We have done some modifications and now it's changed," chief race engineer Xevi Pujolar is quoted as saying by ESPNF1.
Asked if they had challenged the FIA's decision, he added: "No, we just changed it and that's it."