Snap 'em up while you can, we say.
The tricky thing about identifying future classics is that, by the time they're seen as desirable, their values balloon out of control into ballistic proportions. For instance, it was possible in 1969 to buy a used Ferrari 250 GTO for as little as $16,000 when converted into today's money, and now they're worth nearly $40 million. With such a terrifying precedent at hand, it's very tempting to buy a Dodge Viper whilst you still can, as the National Automotive History Collection has deemed the car to be a guaranteed collectors' item one day.
According to the NAHC, the sixth-generation Dodge Viper in particular will be seen in the decades to come as a particularly desirable American-built car (the NAHC's analysis only looked at cars built in North America) that was on sale in 2015. Which is quite a stellar recommendation, considering some properly great US-built vehicles (Corvette Z06, anyone?) burst onto the scene last year. You can certainly see why the Viper was granted "Collectable Vehicle of the Future" status: it's an incredibly rare vehicle, and the mass following it has now means the young'uns who clamour for one now will be the people who'll be buying them in the decades to come once they have enough spare change lying around.
Of course, just because someone says a car will be a future classic, it doesn't necessarily mean we'll see values start to steadily climb. Take the Mercedes 190E Cosworth as featured in the TG clip below.
Though its worth has risen since the video was first aired, you can still get tidy examples for relatively affordable sums (which isn't something you can say about E30 M3s nowadays). But the Dodge Viper has the right set of cards to play in the future classics stakes; it all depends on whether the market in the years to come decides to call the Viper's bluff.