Subaru cars are some of the most stable vehicles on the road. Many owe it to the car's state-of-the-art stability control systems, which automatically senses driving inputs to account for a car's overall control. However, technology is only one of several key players in Subaru's impressive stability, be it a sleek WRX or family-friendly Outback.
Subaru's engine design is a deviant. Its BOXER® engine, a variant of the flat engine, allows an equal weight distribution and a lower center of gravity compared with other engines. This allows a Subaru to turn those tight corners perfectly without rolling. The BOXER® engine takes a car's symmetry into account.
However, a flat engine means the pistons must be arranged in an accommodating way. Vertical pistons will shift the car's weight to one side, a major flaw of inline (shift left) and V-type (shift right) engines. In light of this, a flat engine has its pistons placed horizontally. Not only does it fit a reduced cross-section, it also solves a common problem among engines: vibration.
With inline and V-type engines, the vibrations they emit don't cancel each other out, requiring designers to add more components, which only increases maintenance costs. Subaru's engine are arranged in a way that vibrations from one piston are canceled out by vibrations from the opposing piston. This eliminates the need for specialized components, cutting repair costs.
In fact, this is the rationale behind the BOXER® name. It's like the punches and counterpunches of a boxer.