It seems the FIA can't make up it's mind regarding blown diffusers, they recently looked to place a ban upon their usage and it is now being reported
that they have changed their minds. Teams have been benefitting from using the blown diffusers, which helped to increase the downforce advantages gained through the diffuser. The FIA previously determined that the engine had become an aerodynamic aid controlled by the driver, which was against regulations and they wanted to restrict the use of it this weekend in Barcelona but they have now agreed to a change of date due to a number of 'unforeseen and unintended consequences'. Nothing has been mentioned as to what these consequences are but surely the lack of time the teams would have in order to make the necessary changes would of been a big contributing factor. I can see that in retrospect the FIA were doing this to benefit racing for the fans, it might make the competition more interesting if we don't keep seeing the same teams ahead in every race, and if banning blown diffusers means we might see a different driver taking pole and winning a race, then it can surely only be a good thing?