...if I buy a C6 A6 without nav, how hard is it to add?

TIA,
Mike O.

I'll let ya know in a few days, I just bought a DVD-Nav unit off of Ebay. From what I've gathered so far, there are a couple of sticky issues:

1. The sharkfin has a GPS antenna in it, but no wiring harness for it is installed if the car isn't outfitted at the factory for DVD-Nav. Getting access to the sharkfin seems to require some considerable work with removing interior panels in the car. Most people seem to just mount a new antenna elsewhere.

2. An extra fibre optic and power harness is required if you have the XM/Sirius module installed. It looks like Kufatec sells a kit for this, but for 149 Euros. Ugh.

You also will need to make sure you purchase an appropriate rev of the Navteq DVD if it doesn't come with whatever kit you buy. I believe that revs 5, 6, or 7 will work.

which has all you need including a GPS antenna which I mounted on the rear package tray. I'd be happy to forward an install PDF document if you would like.