Sorry to bust any bubbles, but the TRD lowering springs part numbers have been released for almost a year now. They have been on the 2013 TRD online catalog since it was released back in late 2012.
From looking at pictures of the commercial FR-S's using prototype springs (FR-S First Drive Event and TV ad) I am pretty sure the drop will be less than an inch, mostly due to the lack of camber adjustment on the vehicle.
Here's the thread with the part numbers.
http://www.ft86club.com/forums/showthread.php?t=18091