Hey,
it was pretty easy since I just reused most of the existing wiring that was there for the Asuka tuner (RCA vid/audio in)
My stag has the standard pop up display so I used that. All I had to do was wire in a USB port in the cubby hole near the rear gate. Also downloaded a CarPC skin with auto resume script so it remembers my last played position. Bought a cheapo IR remote from ebay to complete the setup.
Check this out:
http://www.engineering-diy.blogspot.ro/2013/08/car-pc-projectaugust-2013-update.html