I think 997.2 hardtops have stopped depreciating, especially the manual versions of the S and GTS. In fact they may be going up in price. Good condition ones with low miles are getting harder and harder to find.

The Targa and convertible ones still have a little bit more to fall, I think. My ride is year 2010, 28k miles, excellent condition cabriolet 2 (non-S)...kelly blue book says it is $47k. I think it might go down to around $42k and stop there. I think the targa would have the same depreciation curve.