the trailing arms are for the trucks with a 5-link rear suspension, which is the tahoe, escalade, and 1500 avalanches and suburbans. They arent for the pickups

 

Also, the hellwig sway bar may actually be better, just because of the fact that is the same size as the hotchkis, but it is solid instead of hollow, this would make it a stiffer sway bar. But if it has crappy hardware, then maybe the best setup would be the hellwig bar with some different hardware.

The front may actually be stiffer as well, but i dont know how much thicker you need a hollow bar to be in order to be equal to a solid bar.

But I could be wrong, the hotchkis bars could be made out of a stiffer metal or something.