Well I like my GT but will say that the leather isnt that great and this is true. It look sweet and I love it but its not your typical plush leather that you will find in VW or Toyota ect.
As for all the other stuff I have the NAV and wouldnt trade it for anyafter market since it looks clean and is OEM style. There are threads that you can search to buy kits to do this but I dont like messing with that s*** and I dont want a portable unit with wires running over the dash and suction cupped to the window.
The other things I love are the HID headlights that are controlled inside the cabin for where you want them pointed. Also the rear lights are all LED and not that red/yellow plastic covers over a white bulb.
The Bose isnt a 10 inch sub and it doesnt go BOOM when the bass hits so if you are into that then its not for you. However I can turn it up high with no distortion and it sounds as good as I want it to and I am very happy with it.
For $2k more you are getting a ton more s*** on the car and it will help resale but if you want to save the money and just have a bad ass car then go with the sport.
For the auto lights and wipers thats no biggie and just another perk to it but dont forget for what you are getting its pretty stupid not to consider the GT package.
Leather, Bose 6 disk and speakers, alarm, HID, LED lights, auto lights/wipers, NAV. There might be more but I forget.
As for the NAV if you decide against it thats fine but now realize the sport vs GT is only like $1500.