@Antoine: today I've seen in the backyard of our local Fiat/Alfa/Lancia-dealer, where the "Abwrackprämie"-cars are stored, a Citroen XM. It's dark red and has a "V6"-sign on the front fender.

Are you interested? You wrote, that you would like to have a XM.

Yes, I know, that it's not legally to buy and register it again - but here in Germany. As I know, you can make half-legal tricks to export these cars, dedicated for the shredder.
The owner of the Fiat-garage is a nice guy, perhaps I can arrange something for you.
You only must see, how to register it again in Belgium without papers. I guess, it should be possible anyhow (at least make something with the FIN-no... )