I found myself that it makes a huge difference on the cost of the headlamps which country they are for.
The Xenon retrofit isnt the same as the factory install. For one thing the squat sensors on the rear suspension are not usually installed, the new bumper with headlamp washers is not installed and the old vacuum adjustment on the old headlamp angle needs to have a Xenon bracket fitted - which is not easy to obtain as only a small number of people are capable of finding the old parts to fit into the new system.
With the SatNav you need to be sure that you are buying the correct version. The cabling, installation and setup is not such a huge problem.
I haven't seen a 7 CD changer ever...but as far as the other items are to be concerned (satnav and bi xenons) I have them both on stock (new bi xenons for the 203 sedan) and refurbished SATNAV (comand and APS30)...