The controversial diffuser design that was ruled legal 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.

Yesterday's 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.

Nick 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 yesterday's decision will make it difficult for he and his team to compete with the diffuser design necessitating a number of changes to the car.

"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 Heidfeld.

"Obviously before yesterday's 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.

"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.

"The season from yesterday is more difficult as we need to close a big gap between the front-runners and this is never easy.

"But the championship is long so you never know. We need to finish races and need to score points and slowly develop the car and hopefully we will be one of the quickest at the end of the year.

"The philosophy of the car has to change a little bit in how the front wing works and how the flow goes to the rear end of the car. It will take time but it is not just for us it is the same for most of the grid."

The verdict was unsurprisingly good news for Nico Rosberg of Williams, but he stressed he will not be reacting with panic that other teams will now be doing their best to catch up.

"It was good news for us of course," said Rosberg. "It is looking good at the moment for us, we have a good chance to continue to score some good points and be relatively far up the grid.

"It will take many races for them (the other teams) to attempt to make their car work with that sort of diffuser as it is not a given that you are able to make it work.

"I think we do not need to take advantage now, we need to continue into the rest of the season thinking we will develop very well and stay where we are or even move up.

"It is better than being scared and trying to take advantage now. That is not the way to look it."

Brawn GP's Jenson Button currently leads the drivers standings with 15 points and will be looking to add to that as he chases his third successive victory at this weekend's Chinese Grand Prix in Shanghai.