I am wondering if you had found anything out on your Nav update. I have a 14 myself. I'm assuming it's just software and not the unit. I plan to ask a tech at my local dealer.
Anthony, sorry for such a long delay in not replying. I have been on another Forum that seems to be more active. To answer your question, it is NOT just an software upgrade. You have to have a main box (radio) that has Navigation. The type stereo you have (I have Boston Acoustics) is programmed into the radio.
Besides the main box you will also need the "Touch Screen" face plate, if you have heated seats than the face plate must have that also.
If you already have "MyLink" in your 2014 then you will only need an antenna that installs in the back of the new radio that just stays hidden up under the dash.
The main box and faceplate will cost you some money! You will also have to spend about $300.00 getting it programmed, your VIN needs to be added so your able to add OnStar or XM radio.
GEN5DIY sells everything you need, costly but better than purchasing something you don't know if it's going to work or not. Their unit comes programmed they way you want it setup.
Your best bet is to telephone Jarod at 928-505-1383. He will answer all your questions with honest answers.
You can PM me if you have further, wishing you the best of luck. Larry