<p>A system for modifying the handling bias of a vehicle having one or more dynamic parameter sensors (114, 115) which produce sensor signals representative of parameters indicative of the current handling performance of a vehicle, and a vehicle handling performance controller (106) responsive to the or each sensor signal to produce parameter control signals which are applied to parameter control devices to adjust the parameter towards a desired value in relation to the vehicles current handling status, the handling bias modifying system including a signal modifier (506) which receives and modifies one or more of the sensor signals and/or one or more of the parameter control signals.</p>
