Read on Autosport that Ferrari will be dual-tracking. They clearly have the budget to do so. Regarding Mercedes, they are definitely shifting to 2016 now, on both the engine and the chassis.
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Waste of resources. Probably statement was made pre-race, when they thought that they really caught Mercedes and received nice reality check during the race. Unless they will use remaining races for testing new parts, some of which could appear on 2016 car. But that will soon be a case for all teams.