A steering system for a car having two front direction wheels and a number of electronic dynamic-performance control devices; the steering system has a steering wheel for controlling a turn angle of the front direction wheels, and a power-assist device which generates a power-assist torque which is added to the torque exerted on the steering wheel to vary the turn angle of the front direction wheels; the power-assist device has a control unit, which determines operation of the electronic dynamic-performance control devices, and modifies the power-assist torque as a function of operation of the electronic dynamic-performance control devices.