To be honest, the the ride is main thing I dislike about the ST. There's no reason it needs to be so firm. I had a rental Explorer for a couple weeks, it was a 23 base model and it rode so much better. It's probably a combination of the spring rate and the 18" wheel/tires that made the ride better. I wish Ford gave us the option of "Mag Ride" like the Mustangs get.
I am also interested in another spring/strut option if anyone has any suggestions.