No, it doesn't work that way.Engine 1 produces 460 HP, like advertised.
Engine 2 produces 485 HP, over advertised.
Engine 1's owner instantly files a lawsuit because Engine 2's owner paid the same price yet got 25 more HP. Ford now has to defend that in court.
As long as the engine produces at least what Ford advertises, there can be no legal action. Engine 1's owner could not file suit, on the grounds that Engine 2's owner got more HP. It wouldn't work in court.
Look at it another way;
You can't buy medium latte, and then sue because the Coffee Dude with the man bun gave someone else a free latte for whatever reason.