You don't need anything else to use the ST struts, they are a direct swap.
I do recommend picking up the ST strut mount, though (Motorcraft # AD-1098). Stiffer upper mounts will improve your handling performance and steering feel even further. They aren't super expensive, either at ~16 bucks a piece through Tousley. Easier to do it now while you're diving into the suspension.
Joined the dark side.