I am ignorant to any of the 2014 m/y changes, but IIRC, the only items that are exclusive to GT trim is 8-way power driver seat (compared to 6 in Touring), heated leather, dual auto climate, 19" wheels/tires, and true advanced keyless entry. Those are the major items anyway. Can't think of anything else.
It really all boils down to personal preference. I am not a fan of leather seats for cars nor do really have any desire for heated seats (not as long as I am living in Texas). I don't want the expense of 19" wheels (though they are nice).
The only two features I will miss getting Touring w/ Bose and Tech packages is the dual auto climate and the true advanced keyless entry.
This isn't to say if I could get a 2013 GT for a good price I wouldn't consider it, because if I got a good price the extra tire expense might look like less of an issue and I don't have to use the heated seats. Not a huge fan of the leather but could learn to be happy with it.