The product that solved the problem is: BlueTooth Phonebook.
The phone would not sync more than about 5 contacts with the car before timing out and failing. I tried on two different Elantra SE’s and two different Galaxy S5 phones. Something is wrong with the implementation (if not design) that causes these two Korean products to not talk to each other given my phone’s contact configuration (i.e. Google, Touchdown and Outlook apps – plus the phone storage).
Tried the demo and it worked flawlessly so the $2 was easy.
I can’t tell if the app continues to run or caused a setting to change allowing the devices to transfer as they were intended.
I am slightly annoyed by the behavior of the phone/car re synching 450 contracts if ANY contact changes on the phone. I can’t tell if that is the car, the phone or something that this app did. Considering the overall benefit of being able to use the phone through the car – I’ll live with it.
— Updated —
Interesting development. I must have missed it but it seems that the Elantra will only sync with contacts in the phone’s onboard memory, not any of your applications. I’m sure this is documented somewhere – thus it is my oversight but all the same… That’s the root cause.