Good news!!! Cortana on WP 8.1 works great thru the Q5 Bluetooth phone interface. Just sync the phone, start Cortana on the phone, then speak thru the in-car microphone. Cortana does her thing and the results come thru the car system (e.g. calls anyone in your contacts and allows you to speak thru the car system). :-) :-) :-)
Not so important now that I can't sync my contacts from my phone.