I'm going with this...
To be used with the camera kit. Just run the USB to the trunk and into the dac and toslink into my Helix p-dsp.
iPhone 5s (iTunes library/iTunes radio/Waze, etc) to Airport Express via AirPlay. Aux out of Airport Express to Helix A4S Competition. Micro-Precision 5.28 tweeters, Gladen Sub, and Dynaudio MW152 midranges. Jehnert Door Cards and mid-bass'.