Well, let´s wait to see, because everything is possible. And if Williams made a bad thing and the new FW26 became a "loser"?
We don´t know, i guess the new FW26 will be as competitive as Ferrari was in last races last year. But the problem is: and the other teams? They could be improved their cars more than Williams, or not, it´s hard to say now, cause Jerez test days are so relative: they are just test days, and not qualifying or Friday pratice days.
I prefer to wait for the first Saturday qualifying day, at Australian Grand Prix, March 7.