Hallo aus Großbritannien

[uechtel]

Just as a quick fact check: I did not find any Viano offers with "aftermarket" roofs, but a quick search on mobile.de gives the following overview:

Viano 2.2 from 2004/05, ca. 200,000 km
with push-up roof: ca. 17,000 to 18,000 € (2 offers)
without roof: majority of offers between 9,000 to 12,000 €
Price difference: 5,000 to 8,000 €

Viano 2,2 from 2006, 150,000 km
with roof: 27,000 € (1 offer)
without roof (only long "Fun" models): from 13,500 to 21,900 €
Price difference: 5,000 to 13,000 €

Also just for comparison the same with VW T5 models, as here you have usually a lot of cars with "aftermarket" roofs:

VW T5 Transporter (so no "factory roofs"): 2007 - 2009, 60,000 - 100,000 km, 100 hp:
with roof: 20,000 to 21,000 €
without roof: from 13,000 € to 17,000 €
Price difference: 4,000 to 7,000 €

VW T4 Multivan, 2000 to 2002, over 200,000 km:
with roof: 12,900 to 20,900 €
one offer with Reimo roof: 15,000 €)
without roof: 10,000 to ca. 17,500 €
Price difference: 3,000 to 4,000 €

Fazit: The "Multivan/Fun"-like models (= with roof but without kitchen etc.) are rare to get, which to my experience means, that they tend to keep their value more than the standard models. But of course I don´t know about the specilities of the British market.