1- 3.5mm input version
This version accepts input from any 3.5mm (1/8") stereo plug such as iPod, iPhone, Android, whatever. You can even plug in a Bluetooth audio receiver that has a 3.5mm plug on it & then you can stream from an iPhone or Android to this device.
This version also supports iPhone music controls via the steering wheel controls; play/pause, next track, & previous track. BUT this requires that you run another wire (maybe 2?) from this module to the iPhone, to a 30 pin iPod connector. Yes, you can use a 30 pin to Lightning cable adapter & it will work for iPhone 5.
Being that this module plugs into the trunk mounted cd changer plug, you'll need to route this cable/cables from the trunk to the front if the car, along the door sill & under the carpet, behind the dash, etc. Not terribly hard, just takes a little time. I suggest either a 25' 3.5mm stereo male to male cable for audio only, or maybe an Ethernet cable for audio & iPod controls.
This version is not "upgradable" to version 2; the guts are completely different with different PCBs.
2- Bluetooth version (still in work, but this is how it should work)
This version doesn't require any wires to be run at all; the audio is wireless, and the iPhone/Android controls are wireless. The steering wheel controls will control next & previous tracks, and at this point, maybe Bluetooth syncing or power toggle, not sure yet; just a matter of software.
Both modules will display a string of up to 12 characters from the lower ASCII table (up to character 128 I think...?), whenever the radio is put into cd changer mode.
As of now, and I don't have any plans to do this, there isn't a combo board, that allows either 3.5mm or Bluetooth in one module (unless you just want to plug a Bluetooth receiver into the 3.5mm jack).