Well I was semi surprised to see there are almost no 156 V6 left around anymore, there's about 200 odd in the UK that have an MoT and any for sale tend to be well kept ones (or so they claim) that are starting to command money. No idea how much mine is worth but it's definitely more than what I paid for it.And Busso depreciation? Probably not too bad.
Still even if Busso appreciate, they are not cheap to run. Anything gained from an appreciating Busso will not get anywhere near the maintenance costs of one. But that's not the point of ownership!
Without being rude to the Giulietta or it's owners, I can't see any of them other than the QV being worth anything somewhere down the line. Which actually adds a few plus points for the QV over the MA.