Ford Racing also sells the same thing for about 1/2 the price. You will also want Steeda's polyurethane bushings. I did all this when I had the IRS still.
In the end it might have helped "reduce" it, but nothing ever took it away.
If you plan to keep the IRS, then get this brace, the bushings, stiffer shocks and some sticky tires. That will help out a lot.