I think in many ways, you just have to look back at history a bit to determine if true. Look at the 60's muscle car era and the values of those cars today...
My family always had corvettes when I was growing up (ironically up until I could drive). I remember '58, '62', '63 split-window. Funny part about all of them was none of them were considered collector cars in the 70's or any of the other 60's muscle cars. It was not until the mid 80's that their values started to rise and 90's sky rocketed. My father still goes into amazement when he looks at what he owned, what pice he bought/sold them for and what they go for today. I always ask in amazement of how did he not know they would be collectors and worth something later. Much of his responses are like what was said in this post. (they were still going down in value, etc)
Anyway, the point is a viper (any of the years) by simply being american built, high HP sports cars without a bunch of electronics and built in low production numbers will definately be collector cars. Probably not for another 10yrs or more, but they definately will be. I am sure some of the special editions and years will be more desirable than others, but even that is hard to predict.
As for the other cars on the list, they are all very easy safe bets as well. The Ford GT is such an easy one and really has its current value because they no longer build it. If they had still been building them for the last 5yrs, the used ones would be worth much less.
All that said, I have only purchased one car as a collector (100% stock 65 corvette rdstr with all options and 40k original miles in 1988). Sold in 2005 for a 4x increase. Loved the car and wife wishes we still had it, but reality was difficult to enjoy as had to keep stock, all #'s matching, etc. I will not be surprised if the Viper follows that same path in the future, again just not sure when that future point happens.
Lastly, if what I suggest happens (who knows...) I do think having the originality will matter, so having all those original parts we have changed (stock exhausts, air intakes, etc) will matter in value. Anyways, just my guess based upon past history.