S/T sway bar not for boxed control arms??

I was looking in my Jegs catalog at the Suspension Techniques sway bar set since I know our rears can snap. It mentioned that the rear bars cannot be used with boxed lower control arms. I dont get this since its just 2 bolts on each side. I have boxed control arms with 2 holes for a sway bar. Does anyone have boxed control arms and a S/T rear bar? Also is the S/T front bar any better than stock?