JBL has announced the release of a new bluetooth amplifier. http://www.jbl.com/car-amplifiers/GTR-7535_.html
The new amp connects directly to your bluetooth music device so you no longer need an in-dash or under-dash unit to receive the signal, turn on the amplifier, etc.
With the new amplifier installed and wired up you connect your phone and stream music. Now without an in-dash head unit what do you do with your speakers? Probably the best thing to do is take the vinyl/leather off your door cards, use your existing door card material or as I would suggest, use a heavier door card material and cut out a hole for the speaker. If cutting a hole in the material bothers you make a circle where the speaker will be mounted and drill as many holes with a drill as it takes to allow good sound to pass through. Mount the speaker on the BACK of the door card and reinstall the vinyl/leather material covering the speakers completely. Wire the speakers to the amp and install a powered woofer under the seat (such as http://www.crutchfield.com/p_1...ssPro-SL.html?tp=114 ) and enjoy completely hidden audio.