Yes... all cars have engines, but not all cars have Volvo engines. Yes all cars have 3-point seat belts, but not all cars have Volvo's seatbelts (pretensioners, self adjusting height etc etc etc that go along with it)... The Ford and Mazda are sharing basic architecture with the Volvo, but that is about it. Ford and Mazda might have curtain airbags, but I seriously doubt they are the same actual unit. If you ever have a chance to compare airbags components (between cheap and expensive cars) I think you would be surprised at what's inside! And they have to design the component into the vehicle such that it is effective and deploys at the right time etc, not only so it protects passengers, but also so it is not the cause of injury.