Best Car Integration for Windows Phone 8/8.1?

I have a 2014 Volt with MyLink (same as your intellilink). It works great. If you hold down the voice command button on the wheel for about 2 seconds it will launch cortana, and you can operate pretty much hands free.
 
some head units (double din sized) are starting to come with HDMI, so adding a miracast unit in the dash is possible, you would just have to still touch the phone to launch apps and whatnot. I currently use an alpine iva-w505 (2008/2009 head unit) with a KCE-400bt that I had to risk installing a european firmware to get my lumia 920 working 100% on. Most new, stock units with bluetooth should work fine.
 
This will only give you just music, all the quality is gone, since AUX is not the big concern from manufactures, if you like to have a good ?udio quality both, BT or Aux is out of the question, you wont get quality. I don?t know if chrysler is using the same system Fiat uses in their cars, Fiat?s Blue ME is based on Windows, and they should work very fine.
 
My wife just bought a 2015 Chevy equinox with mylink and it is amazing, the onstar app for starting and looking at the car information also the phone link work great too, when I call my pic on her phone shows up on the screen, very kewl.
​I just need to find out how to launch contara from the button on the wheel and not from the phone
 
Instead of a short push of the wheel button, hold it down. Cortana will launch then you can let go of the button. Usually about 2 seconds.