Welcome to C-Brats! :thup
Others here will know much more that is specific to 16's, but since no-one else has replied yet, I'll throw in a few things to get you started. I've never owned a Whaler, but I get the feeling they are like C-Dorys in that they are really practical and have a dedicated following.
So first off is that all C-Dorys (not that this is unique to C-Dorys) have a cored hull, and a number of other cored areas (decks, transom, some "walls," etc.). So you want to make sure that is not compromised, or that if it is, the price and your desires for a boat/project reflect it. They are not any more prone to problems than any other production/cored boat, but it's something to look for.
If a boat has mostly been stored on the trailer/indoors, you have a head start of course, and much less likely that any problem in the core "grew, unnoticed."
I don't know about the 16, but with the 22 (which I'm more familiar with) there was an older design (pre-1987) and that had a plywood hull core, and then they slightly changed the design (1987) and I think that's when they went to balsa core. Both can work well, main thing is to keep it dry.
After that, the one thing I have noticed on the 16's is that the window designs have changed over time. Seems like, IIRC, the oldest ones were maybe just a slab of something clear (not sure what) fastened to the window cutout. Then as time went by they went to the older (silver) design with the actual window frames, and then eventually (early 90's?) to the current white frames.
And maybe this is in backwards order, but do you know that the 16 comes in two basic designs (at least nowadays)? The "Cruiser" has an open V-berth, then small cabin with helm (open back, which can have a fitted canvas zippered door curtain), then cockpit. The "Angler" has a closeable storage compartment (smaller than V-berth), then a small cabin with helm, the open back, then the cockpit. On the Cruiser the helm area is further aft, due to the V-berth, and apparently it can be a bit prone to being stern heavy, whereas the Angler tends to have better balance, fore-and-aft, because the helm is further forward. If I weren't planning to sleep aboard, the Angler would be my choice, and even if I were going to sleep aboard, I might consider the Angler and some good cockpit canvas over the Cruiser.... but that's more debatable.
I've only been on one 16 Cruiser that a C-Brat/friend used to own - we went out a few times for the afternoon. I believe his had a 40hp Honda, which of course seemed perfectly fine. So I can't speak to the 25hp. If it were enough power, I suppose the lighter weight would be advantageous on the can-tend-to-be-stern-heavy Cruiser model.
As to price/value, there is a sub-forum here that can be helpful. If you go to the area where the classified ads are, you will see a sub-forum called something like "Marketplace Reference." That contains pages of old ads. The actual selling prices aren't shown, but you can see the asking prices, and often times you can get a pretty good idea of where that stood as compared to the selling price, by how quickly it sold, if the price was reduced, etc. And there is a good sample size.
There are quite a few people here with 16's, so I'm sure better information will be along soon. Happy shopping!
PS: There is one fellow here (but I can't remember his user name, dagnabbit!) who has an older 16... I think maybe 1980's vintage. He had the older windows and I think replaced them with custom, opening units sort of like the "safari" windows on an old VW bus - they looked pretty sweet. I think it was the same owner who had some issues with some built in boxes at the stern (water had got into them), and there was some discussion of them, with photos, etc. Might be worth digging through the boats list (up top) and arranging by year and model and then looking in the photo albums of the older 16's. I think the boxes might have been unique to the older ones, but not positive.
