When I had the ST and my 2011 Fiesta, I measured the floor depth on both of them and realized they are about the same. I have pictures somewhere, but not sure where. This was with the floor placed on the low setting. What eats up cargo room on the ST are the stantions for the upper floor position. They jut out into the cargo area and reduce the amount of space for suitcases. I am considering removing the dual floor on the ST and use the 2011-13 rear cargo trim and floor. The spare sits up an inch or so over the non-ST.