Initially I did set up my Gear S to connect to my car's BT for both calls and audio. Everything was good as long as I had either my Note 3 or my Gear S alone. But whenever I had both, my car would always pair with the Gear S instead of the Note 3 until I changed it manually. I never could figure a way to make it default to the Note 3. Gear S worked just fine with the car's BT, but I found it better to just delete the Gear S from the car's radio to force it to use the Note 3 instead.