All vehicles fitted with power steering systems require a special type of fluid in order for them to function correctly. When pressurised via the power steering pump, the power steering fluid activates a piston within the steering rack which assists the movement of the rack and pinion. This, in turn, reduces the amount of effort required to turn the steering wheel and makes it much simpler to make small adjustments to your racing line.
When using a standard power steering fluid, as used for road going cars, for competition purposes, there is a possibility of the fluid being affected by the increase in temperatures as well as the added, sometimes vigorous, steering inputs. This is why it makes sense to upgrade to a high performance power steering fluid such as those found in the selection above. A competition power steering fluid can help to reduce the fade that occurs when the fluid becomes hot and loses pressure. This essentially means that the steering becomes heavier, making it harder to be as precise. Synthetic fluids also help to reduce the drag on the power steering pump and keep all components working efficiently.
As the main way for a driver to understand what the car is doing is through the steering wheel, it makes sense to ensure that you have the best feel possible through the steering wheel, so that you can press on in confidence.