Another difference is the socket screw holding the mast receiver in the bottom of the boat. This has been upgraded with stronger steel, and rolled thread construction, which both reduce chance of it breaking off (which has happened to some TI's)
Actually, I am trying get help from the forums in constructing a list of modifications made to the Islands over the years, for exactly the kind of questions that started this thread. Unfortunately, this has not attracted the assistance I expected, and need. See topic
http://www.hobiecat.com/forums/viewtopic.php?f=71&t=46735