So, after finding this thread, and scouring over other similar threads from 2gfusions and 6gmustangs, I took a chance and found a new Sync 3 APIM (non-navi) with screen on eBay to replace my 2015 Sync 2. While I couldn't verify the part number with any diagrams, it had the stepped side, so i risked the purchase (knowing I could probably resell it if necessary). It turned out to be a perfect fit, after I swapped my Sync 2 brackets.
Thanks to UPS, I had a few extra days to wait for my ELM327 cable to arrive, but being my impatient self, I figured I could at least test fit it and see what happened. I was surprised that it worked right out of the box (with some minor issues). Radio came to life, climate control worked, phone, settings, etc, all seemed to be good. Navigation showed a fault (but that was because it was a non-navi version) and I didn't have my heated/cooled seats and steering wheel controls, but I could experiment.
Fast forward 3 days and I finally get my programmer, load up FORSCAN and work through programming. Now, I'm fairly adept at tech, so this wasn't really a challenge for me, although it still took some trial and error to get things right. Ultimately, I have everything working, but have noticed a couple of issues that hopefully can be addressed.
Somehow during the programming today, I lost the ability for the E-911 from my phone. Normally when you pair a compatible phone, the system asks if you want to turn E-911 on. This was working throughout the week until I started reprogramming today.
Also, my Entertainment option on the IPC used to have an option to select bluetooth devices when connected, now it no longer does so.
Any ideas from those who've programmed before?
I have yet to test the Apple CarPlay as I am waiting for the USB hub to arrive. Once that's there I will test that and report back if there are any issues.
I have to count myself as very lucky, as all in I am under $400 for all my pieces. It can be done by yourself a lot more cost effectively than the kit solutions online ($1200++) as long as you do the research. Boards like these are truly very helpful and great sources of information to help get you through.