Adjustable anti sway bar links
 

Since these are supposed to be installed and tuned with the driver in the car does that mean they are designed to be used with only the driver in mind or can a passenger also be present for a ride (after install) w/o defeating the integrity of the install parameters. In other words are they for racing only.

Adjustable end links simply allow you to tune swaybar pre-load based on whatever load setting you desire - driver in, driver out, pass. in, pass. out, full tank, half tank...you get the idea.

When you tune the swaybar endlinks for a specific load they still work with different load levels, but the handling characteristics will change somewhat. The degree of impact is dependent on the load difference vs. the 'tuned' load and how close you are to the handling limits. In normal day-to-day commuting you'd probable never even notice.