Copilot is by far my favourite navigation app with it's many customisable features.
I have however noticed that CoPilot does not have an option to switch on HFP (Hands Free Protocol) instead of A2DP like some other apps do have. This would allow you to listen to the car Radio or CD and voice instructions will still come through like incoming phone calls. Currently CoPilot can only issue voice instructions when selected as audio source on your car stereo.
More info here: