Never did Supersprings, but did do F & R swaybars and Torklift Stableloads.
I have to say, each improved things pretty much equally. I felt a big difference after each step, and am now extremely happy with the control.
Just last weekend I had a massive emergency stop. Thanx to one of our infamous A$$H0&^% Seattle drivers cutting me off, I had to dynamite the brakes, locked up my trailer AND had the anti-lock kick in on the truck---FULLY LOADED.
My setup is top heavier than Dolly Parton. Everything stayed in control. Worth every penny. Of course I wanted to kill the SOB that cut me off, but with my tire iron and not my truck.... Grrr.
**Disclaimer - no I don't really want to kill anyone, it was a figure of speech. I like my truck too much.