Think you'll find a thread in the D40 section (maybe) that lists the main differences between the two. The ST was introduced last year some time and there was quite a number of people interested in the differences and the thread did get added to as deliveries started arriving. There probably a number of threads around that list some of the differences
Beware of the thai ones, if my king cab is anything to go by (and others), they'll be shithouse on fuel.
My Kingcab STX is a noticeably lower spec than the dual cab stx also