I'm sceptical about the assumption everyone seems to be making that the "works" teams will automatically have an advantage. Because each manufacturer can only homologate a single specification of engine, there will be no engine advantage for the works teams. Even if they manage to subvert the engine freeze and sneak in performance upgrades under the disguise of "reliability," as they have in the past, they will still have to make the same changes on all the customer engines. Certainly the works teams have had the benefit of being able to influence the engine design to better fit with their chassis and aero plans, but that is by no means a conclusive advantage. The customer teams are in a much better position in this respect than Brawn were in 2009. At least they have known the parameters of the engines they need to design around for a long time.

A better assumption I think would be that the well-resourced teams will have an advantage, which would mean a big 4 rather than a big 3.