There is really very little reason the cars can't be going around as fast as they can at this point, to a degree. Last year it looks like here for the race Hamilton did a 1:27.2 in Q1 which lets presume was on the hard tyre as, afaik, Kimi was on. Then he did a 1:25.2 on softs in Q3.
Maldonado did a 1:24.8 at the two day test just after that race which is.... questionable, either the site I'm looking at had that down incorrectly, maybe they did it on supersofts and no one else ran them at testing or maybe they just ran way under weight trying to see what the chassis/aero was capable of.
I wouldn't be surprised to see them be a couple seconds faster. Maybe hit 1:25's on hards, 1:23's on softs maybe, potentially even lower from a couple of people, more chance if anyone breaks out the supersofts but I doubt the fastest teams have much want to use them and show off their speed in testing.