I'm afraid to admit given the content here, I still have my stock '03 endlinks attached to my Hotchkis sways. They haven't broken and I just don't think I could tell enough difference to make it worth the tim or money.
Here is JR's take from the FAQ sticky:
"Do I need upgraded endlinks?
Maybe. The purpose of the endlinks is to attach the swaybar to the suspension arm to transmit the forces applied to one into the other. Therefore all the forces applied to the swaybars will be transmitted through the endlinks.
The stock endlinks are replaced because the stock units are very flexible and the force that should/could be applied to the swaybar and/or suspension arm is wasted flexing the stock endlinks. Also the stock endlinks can break when used with much larger bars than stock.
<22mm swaybars: meh.
22-24mm swaybars: Maybe. This decision should be made between your desire for performance and your wallet's desire to remain full.
>24mm swaybars: Yes.
Again please PM our vendors to get manufacturer info and pricing.