I kinda wonder if you actually received the springs that you ordered. Have you double checked the part numbers that are marked on the springs themselves? I had a set of Eibach Pro-Plus springs for a while and I don't recall the car being as low as yours appears to be in your pictures.
I do have Steeda Sport springs but they are for the coupe, not the convertible.
steed makes sports springs for certs too.
and yeah I'm sure i received eibach pro kit springs, but i think I'm going to order steed Steeda 2005-14 Mustang Convertible Sport Springs - Made in USA 555-8220 - Free Shipping!