Its interesting that many of the British magazine reviews I read about the Z8 are negative on the styling- and some commentators like the new BMW styling direction. This is consistent, if nothinng else, but its fair to say I disagree with their opinions.
I am not surprised to see a used Z8 depreciate. There are new ones to be had and the world economy has cooled off a little. But I am surprised to see it with relatively so few miles. That is very interesting.
I dont know if you had the kind of mania that we had here for the Z8- one or two reportedly sold for $500,000
I suspect it wasnt quite as heated in the UK. And then, as you say, its LHD.
The question is- what happens ~10 years after production ends? I would imagine you take your depreciated value and then it will begin to appreciate- but the degree of appreciation will be directly related to the long term general consensus on the car's shape and if there are any mechanical/structural problems that become evident on long term cars. My own guess for the USA is: the cars will have a slow, steady appreciation but it wont make one wish they bought a Z8 as an investment.
Maybe in 30 years or so the car will be worth that $500,000- but mine wont because it will have ~234,000 miles. The best investment is one that makes you smile- and in that department the dividends have been rolling in from day 1