David, So would say that a street car that will see a track or auto cross a few times a year benifit from these or not really?

He looked into it so good the website is offline :).

Looking forward to these :hail: .

Can we get before and after test results on these bushings?

So would this be an improvement over greased up Delrin bushing shackles?

There is benefit, I'm not sure how much. When we switched to this type (Cat 5) the rear felt more precise & it let you know what was going on back there a little better. We have this Hotchkis system on Deanna's second gen Camaro which is winning.
In a back to back test, comparing it to Delrin/Poly bushings, I think the difference would be small. No way do you ever want a solid delrin or aluminum bushing up front on a leaf spring. It would cause corner exit oversteer due to binding. A solid bushing on the rear leaf eye is not so bad, but a stock front & poly rear on the leaf eyes is next best to this system.
David

Just trying to connect the dots here.

As far as a leaf spring rear suspension is concerned, this setup with an adjustable sway bar, PTFB comp rear leafs, would be the cats meow as far as a leaf sprung suspension could be for a autocrossed car that gets driven on the street.

How would a watts link affect a setup like this? Would it interfere with the already limited side to side movement?

A watts link defines a roll center the leaf springs also define a roll center. If you matched these roll center you would have less bind.

I would use these and a spherical in the front spring eye.