The middle holes are medium, the ones closer to the bar are stiffer, the last set is the set you seem to want (although, why get aftermarket sway bars if you're not going to tighten the Urgh out of them)

Cheers,
Joel

 

actually i have the perrin rsb and i was wondering about the settings. The difference in stiffness of a sway bar comes from the twisting in the bar right? not the bending of the part from the bar to the endlink? But, the adjustments on the rsb are just different lengths for a lever that exacts a torque on the bar, but since you change the hole accordingly on both ends of the swaybar, how does that increase the ammount of force exerted on the other end? the lever length is just a multiplier for torque and it seems to be on both ends of the equasion, unless the actuall lever itself is bending and its not a twisting of the bar...