I don't want to rain on anyone's parade, but dropping the diff, and not changing the arc of the swing arms, is a recipe for problems. If you notice Calmini's set up, both the 2" and the 3", use different drops and it has to do with the a-arms different arcs.
Now, anyone can sell you anything (and I guess if you are in Taiwan, you can sell knock-offs of patened parts), but whether they will help or hinder is the million dollar question.
Remember the adage, "Let the buyer beware".