USB audio support in Android 4.1?

I recently switched from an iPhone to a Galaxy S3. While I don't regret the change in the slightest, my one disappointment has been the inability to run a USB cable directly from my phone to my car's stereo to play mp3s, Pandora and iHeart Radio. I have read that there are some round-a-bout ways of accomplishing this through an external digital-analog converter, but as far as I'm concerned the additional cables and equipment defeat the purpose. I know that Jelly Bean includes support for USB audio, but I'm not really a techie and have had a hard time understanding exactly what level of support it provides. Most of the people discussing this on various Android forums use terms/concepts I don't completely understand and/or contradict each other. Basically what I want to know is, once Jelly Bean rolls out to the GS3, will I be able to plug the device directly into the car stereo via USB like I could with my iPhone or will I still have to go through an external DAC? I really don't care too much about the ability to control the device through the stereo head unit. Support for this would be nice, but not necessary.