That is a real nice unit. I am not technical installer but I have always dropped money (wasted) on audio video installs in each of my many cars. It would be the very first thing I would do when I bought cars. My two cents - for you this would be a big upgrade if you decide to move forward with it. The 8.4 uconnect is a great unit. Though it could have been a lot less cumbersome. What I mean is that when you look at the screen a lot seems to be going on. Aftermarket units are usually more refined with their functionality.
However, with this particular unit and the difference it will make for you vs the 5" inch screen will be a world of the difference. But with any aftermarket install you need to confirm if the unit is plug and play, do you need adapters or cut the factory wires to connect to the factory harness. Whenever you start cutting into the factory setup your warranty is automatically voided. Now if something is to go wrong, the dealerships default response will be to say the problem is coming from the aftermarket install. Albeit they didn't diagnose anything but it will be their default response. I have had experience with this time and time again. If it is a simple replacement by removing the current head unit, perhaps cut the molding only to fit the new head unit and most importantly it connects to the existing wiring harness then you should be fine.
The cost in my opinion is not your real issue. It is cheap compartively. Any simple upgrade to audio installation at a reputable installer will be at minimum $2,500. My worry is how it will impact your warranty.
Also I would wait until the factory unit with Apple AirPlay comes out. I would simply upgrade to that factory unit and hope it's plug and play with the factory harness.
Hope I am making sense here.