I would guess that because..

"The kit also includes new replacement 4130 alloy tie rod adjustment links, that due to the system's change in configuration, are longer than stock. This added length helps reduce bump steer angle over stock"

...that bump steer would be less than that of a stock system. Perhpas I am incorrect. Sure if you have the stabilizer already then why not go ahead and install it. But what I was saying is that if it has LESS bump steer angle than a stock configuration then you may not need it as much.