Originally Posted by artdohc
Even though pre-S197 Mustangs didn't have one?
Different suspension arrangement.
But whether you're talking about the S197, Fox, SN95, or New Edge, there is always exactly four OE links present. You need all four, else the axle will not be under control in at least one direction.
In the S197, you have two lowers, one upper, and the PHB.
In the Fox/SN95/New Edge, you have two lowers and two uppers that are skewed toward each other in plan view to provide lateral axle location.