Can I get some education on pre-loads and what's their purpose?

Through some search, I found that the adjustable front endlinks allow the driver/mechanic to set the car to zero pre-load on the front sway bar, having a zero pre-load basically means that the car will react equally in both direction when making a turn. Is this right?

Does the car always have to be on zero pre-load? Or is there other settings?

And how to adjust the endlinks to have a zero pre-load?

 

Found this link, for someone who wanted more information.

 

adjustable endlinks are used frequently on coilover systems where you corner balance your car with the endlinks un-linked. after cornerbalancing, you place your car on a known flat surface (or just do it on the weights), use adjustable endlinks to put ZERO preload on the endlink ends so that your swaybar has no effect on the corner balance.

endlinks with preload will distort the cornerbalance (sometimes in extreme cases will even slant your car).