The controversial diffuser design that was ruled legal by the FIA's International Court of Appeal on Wednesday has understandably drawn mixed opinions from Formula One drivers.

Brawn GP used the double diffusers in the first two races of the season and dominated in both while the two other teams who have used it - Toyota and Williams - have also been very competitive.

"I did hope they would be declared illegal so that we would stand a better chance of achieving our goals of fighting for the championship, which will be a lot more difficult now," said BMW Sauber's Nick Heidfeld.

The verdict by the ICA means the seven other teams now need to act quickly to incorporate the diffusers in their own designs in order to compete, however this weekend's Chinese Grand Prix undoubtedly comes too quickly for the majority of those teams.

Heidfeld finished 10th in the opening race in Australia in his BMW Sauber but improved to second in the rain-affected Malaysian Grand Prix.

However, the German believes the decision will make it difficult for he and his team to compete with the diffuser design necessitating a number of changes to the car.

"Obviously before the decision the team was working hard on a solution and from what I understand we will have a big aero update in Barcelona most likely including something on the diffuser," he added.

"However it is difficult to create something as extreme as the other teams have because then you have to change a lot of things on the car."

Two-time world champion Fernando Alonso, meanwhile, was a little more optimistic, though conceded it would be some time before Renault will become competitive.

"We will try to do our best," said the Spaniard. "We will try until the last opportunity."