No pressure! Got it!
After researching this a bit further since I plan on doing this I found out that the Dash Kit / Harness from Metra still isn't available. I called Metra and talked to them and they said the kit won't be out for a few more weeks. So, if you see this kit on someone's website, they don't really have it. They're just taking orders and will end up shipping it to you when they get them in.
The way I see this process is this..... I can get the aftermarket stereo (nav, bluetooth, etc.) installed and will definitely benefit from that because that is better than the factory Shaker 500. I'm betting Sync will work if I get the necessary adaptors (the one I linked to above), but if it doesn't it shouldn't be long before the issue is resolved.
So what might happen is that I have an aftermarket stereo and Sync will be disabled for a while. But, I hope that doesn't happen.
It might just boil down to whoever the installer is and how much he/she understands the entire process and how they should work together. From what I've gathered so far, NOBODY knows a lot about Sync.