As for why Ferrari are not up to speed, it certainly may have to do with the Bridgestones, but... the decision to update the 2004 car to 2005 spec, was not a good call - you can see it in the pics, they did some serious kit bashing

the frontwing is not integrated (pics from Australia) - and the results are showing it.
Rumours say that the 2005 car could see real racing as soon as Bahrain, but I wonder if you decide to cut down development time by one month is gonna do any good...
Renault build a car quick out of the box - which is very good and show that Flavio still knows how to run it - and leaving all the others playing catch-up.
Red Bull racing Ferrari's

I bet DC didn't think about that, before the season actually started...