I was actually quite curious regarding the Ferrari Marketletter but could not be bothered to subscribe.
By incident I came across this link: http://ferrarimarketletter.com/file/v3804forwebcavallino
which reveals an edition online. I have put this edition also in the download folder. Apart from all the adds and publications it does have the known "asking price index". Not really shocking but nice to see. Interesting to see the 365GT4 2+2 and the 400 GT/A are slowly climbing and the 400i GT/A and 412 are declining over the past 3 years. This is however for the US market and prices overhere in Mainland Europe are quite higher (not to mention the Euro/Dollar exchange rates). Perhaps this is why quite a few are imported back to Europe from the US.