If prospective buyers talk to the guys behined the scenes, who have to repair these rolling disasters, then they will be VERY cheap to buy. I tell my customers to skip right over the 355 and go for the 360. But love is blind, and people will continue to buy crappy examples and wonder why they have to put 20k into it the first month of ownership. Obviously there are exceptions, but they are VERY few and VERY far between. Yes they are a beautiful car to look at and listen to. Nothing like it really, but it is thee most expensive later model Ferrari to keep on the road bar none. They will continue to sink in price, and become a car like the TR. Cheap enough to buy, too expensive to fix when broken.
with all due respect, and without trying to create a controversy, ALL ferraris have dipped (or will) below 50% of their MSRP at some point or another (even adjusting for CPI). As for the original question, I actually ran developed a price evolution statistical model (including over 15,000 data points) and came to the conclusion that all cars bottom out at 26-28 years of age. Thus the F355 has not yet bottomed out.
I think that is a good comparison to the TR. Is it the infamous valve guide and headers issues you are mostly referring to? Assuming a nice 355 that had the proper repairs done in these two areas, would you still give the same advice to skip to the 360? To you, what would constitute the "exceptions" you refer to above?
Obviously the exceptions would be a 355 that has been updated with new guides and valves, cylinder sleeves, aftermarket manifolds and converters, updated release bearing/slave cylinder unit, correctly operating heating and A/C system, cooling fans updated, airbag harness update, and fuel block recall..I could go on and on.. If items such as these have been taken care of by a caring owner, then buy with confidence. But you will be hard pressed to find an owner who will let go of such car at market price. You will pay a premium for such a machine, if the owner would even sell.