Have the Eibach pro springs for the 2011 gt, with the stock STR.T's love the drop and not too bouncy except where the road is jacked up.
if you keep the stock struts you dont need the strut mounts. If you change to say the koni str struts you have to change them. I used the gt500 strut mountshey Cobra1718, did you have to do any modifications to the rest of the suspension? Was looking at the P springs and it says you have to use the Ford Racing strut mounts and dampers. did you have to do this?
Im running Steeda Sports with Tokico D-Spec and I love them. I tried the sports with Koni STR.T's and it was a little to hard of a ride. Love the adjustability of the D-Specs!