I am not sure of what harness I need and I have already installed an Alpine 9857, but there were two harnesses behind the stock HU. I am not sure if one is for the dash and one for the radio or what!
Any help would be great I will get some pics up later today

 

I don't know if this will answer your question but I've just replace my OEM radio with an Pioneer. I gave the installer the Modifry-DCI and a hardness that I also bought with the DCI and eveything seem to work fine.

 

The DCI only taps one line from the dash, the mute line on the stereo and either a plug in for the hard wired version of the IR bulb.

Everything else is power (red and black) and speed line (grey?)