Hey again everyone,
To my surprise, it seems my suggestion to turn off Wi-fi is working! I haven't experienced a single drop in connection during my week or so of experimenting with this workaround. Granted it's a bit of a pain as every time I step foot in my car I would have to manually turn it off, but nonetheless it appears to work now.
Folks, I encourage you all to give it a try and let us all know your results. I know it's a long shot, but I'm hoping it'll help you guys out like it did for me. Obviously there are a plethora of variables involved as I've also tried all of the other recommendations as well (reset BT settings in car, in phone, hard restore with no backup of phone, etc). Your mileage may vary.