Talked to a buddy from my PCA days and he was saying late the 911 air-cooled market is already showing real signs of well, cooling off. Seems that the days of the $150K 930 models are gone, with some recent sales in the $60-70K range, even for superb examples.
Rare cars and special models seems to be still fetching big bucks, but the standard air cooled cars are dropping fast.
I know someon that paid just over $100K for an 87 Turbo last fall, and he's banking on selling it for a big profit this summer.