In the pursuit of aerodynamics, Subaru has even achieved outstanding CD values across all models – 5-Door, 4-Door, wagon and SUV alike – as a way of contributing chiefly to stable high-speed driving and better fuel efficiency. The 5-Door, wagon and SUV feature various concepts incorporated into lower rear end of the roof and the bumper to achieve this. The WRX STI also generates impressive downforce with the large roof spoiler, while diffuser functions in the rear bumper help to rectify airflow underneath the vehicle. A large rear spoiler mounted on the boot lid of the 4-Door WRX STI delivers powerful down force to help eliminate any lift. Both the 5-/4-Door models have covers mounted underneath the frame at the front and along the side of the body. These covers control the flow of air beneath the car and further limit the generation of lift. This maintains a constant balance in the way the front and rear tyres are in contact with the ground, resulting in stable high-speed driving. The stability that these aerodynamic additions deliver brings about greater driving confidence, which ultimately enhances driving enjoyment for all.