LCA's w/ tabs and bar

I have the 70 sway bar with (almost) new rubbers and links for $100 plus shipping if you got the lcas from Eddie.

I may be interested but I may go with a set of Hellwig bars.

Does anyone know what the difference is between the regular solid bar and the "FSB"? I called Hellwig and the girl from tech support was no help. She just told me it has to do with wheel backspacing and to look at the install directions for more info. The problem is that there are no directions for the "FSB" kit on their website.