Red Bull team principal Christian Horner and Ferrari counterpart Marco Mattiacci have both revealed they considered launching a protest against Mercedes following the German Grand Prix.
Mercedes were allowed to change the brakes on both of their cars in the wake of Lewis Hamilton's heavy smash in qualifying on Saturday.
Hamilton crashed into a tyre wall following a right-front brake disc failure, resulting in Mercedes switching from one supplier, Brembo, to another in Carbon Industrie.
As Nico Rosberg had Brembo on his rear tyres, again Mercedes changed brands, which ordinarily is not allowed without penalty once cars are under parc ferme conditions post-qualifying.
FIA regulations, however, state a team can change a component that is "similar in mass, inertia and function to the original" and avoid any punishment.
Rosberg and Hamilton went on to finish first and third in the race at Hockenheim, the latter from 20th on the grid.
When asked whether he was surprised at the decision, Horner replied: "Absolutely. It is a change of car specification.
"If you change it like for like that is one thing, but if you change it for something made by a different manufacturer that has a different characteristic, and as described by the driver himself as something different, it is an interesting precedent.
"But it is not something we are going to protest. It is really down to the stewards if they are happy with it, otherwise it sets a precedent going forward.
"We obviously now need clarification because if you can do that, then what else can you change? It will be interesting to see what was the justification."
It was suggested to Horner that Mercedes could have changed supplier due to safety concerns, but he said: "We are running the same material on both of our cars as Lewis was yesterday, so it was safe on our car."
Mattiacci also confirmed the situation was mulled over as he said: "We discussed it internally.
"But we decided not to move forward on this because I don't think we wanted to get into it."