No problem. That's how I understand it anyway. The sliders are nice, but they probably fit into the category of "cool things I did that I don't really notice when driving". They definitely go with the theme of optimizing how my car functions, but realistically they probably won't make my car faster.
Oh, another benefit of the sliders- they allow less lateral movement of the springs. Shackles have bushings, and because of the give in the bushings the springs can move side to side when the shackles put load on the bushings. The shackles, being several inches long, also magnify this effect because the shackle acts like a lever arm between the spring eye and upper pivot. Because the pivot and spring eye are in the same place on the slider, there's no lever arm, and the bearings and spacers don't allow as much lateral movement as the shackle bushings do. All of which help reduce the side to side movement of the rear axle, which is important if you've jammed really big tires into a space that they barely fit in. Like my 295's in the stock wheel tubs. ;-)