The result is more downforce. Much more downforce.
The elephantine rear airfoil bolted to the rear deck of the Dodge Viper ACR is not only highly functional, but it gets credit as being the first mass-produced carbon fiber-reinforced polymer (CFRP) wing on a production car. Rear wings on high performance vehicles are designed to counter lift. Without aerodynamic aids, most vehicles become less stable and have reduced grip as velocities increase (worst case, the vehicle actually flies as did the Mercedes CLR at Le Mans in 1999).