Adjustable end links are nice because your frame, bushing mounts, and endlinks mounts aren't always perfectly symmetrical. You also might need to adjust your endlink mounting points when corner-balancing. You want zero preload on your swaybars, so to do it right you should disconnect the endlinks, corner-balance, adjust them to zero preload and then reconnect the endlinks. It's a fine-tuning kind of thing that makes the difference between 1st and 2nd: it's a very small gain, but real.
Unless you're running coilovers and corner-balancing the car correctly already, it's worth absolutely nothing.
And yes, there are much cheaper ways to make them. $50 worth of parts from McMaster-Carr would do just as well, and $100 worth of parts would be better quality. Or you could buy a RH and LH die, and cut and thread a stock endlink, and just put a hex RH/LH shaft in the middle.
starjammir, that was a worthless BS post-whore response. You didn't have a clue what these were for, so why did you post? I'd prefer an honest "I have no idea why you'd need them" to your "if you're racing you'll need them" crapshoot.
