At the same time Button said he has some improvemets to make on McLaren which he needs ;D
If he says he has some improvements, its probably set up ideas. If he had said "we have", or "the team is working..." then its probably updates/new parts.
Doesn't matter much either way, because I'm sure they are ALL working on updates and new parts for either Barcelona or the 1st race.
From their hints though, seems like Mercedes is the one with the most stuff "under their sleeves" or at least the ones with the most development work to do... Red bull seems quite up there in the pace race, but they are probably working on reliability; which cost them last yr's...
Right now, i think Ferrari has the best car (so far) to start as a basis. It has been very reliable and consistent over long runs, and not bad on shorter runs and raw pace. Both the drivers are quite comfortable, which will make it easier to start/continue building from where they are now.
Came out fighting indeed.