OK, so I got it to work, sorta...
I uninstalled the AR Unchained, and install just the regular AppRadio ...
Once I got my Chromecast to log into my P6 via Tethering, I then had it 'Cast'
it took a few moments and the 8100 was showing me the screen to syncronize the screen. So I pressed the white dots, and then got the little video...
The down side is that the resolution is really bad, and I had to press the screen to have it do anything about 2 ties as long as you would normally. Basicly 1 second from the 1/2 second it might normally be.
I tried putting the AR Unchained back on, but then it wanted to syncronize the screen again, and that doesn't work.
So I can now say I got it to work, but I"m not happy with it.... most people are not from what I've read.... so if you can do Android Audo, or CarPlay, they are WAY better IMHO
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Here is how I got it working...
Buy a Chromecast, I don't think it matters if it's v1 (long one) or v2 (round one)
Install AppRadio, and ChromeCast on your phone
plug it onto the HDMI port on your TV and switch to that port.
when you see the chromecast on your TV, use your computer to find it www.chromecast.com/setup
follow the setup
have it connect to your phone via the HotSpot (if your phone doesn't do that then this whole thing is Moot)
Once you can see your phone on the TV you know you followed the instructions right up to this point.
Take the CC and your phone to the car
plug the CC into the HDMI port (and USB power) and turn on the car. It will take the CC about a minute or 2 to connect to your phone.
Launch AppRadio and follow the instructions there (mostly just agreeing to things)
Have your phone 'Cast'
It should then have you press the white dots on the stereo to calibrate it
once it's done, there is AppRadio in all it's glory
I hope I didn't miss anything... 