There was a list of things necessary for a car to become a classic that (I believe) Classic & Sports Car (a UK publication) devised with the help of the collector community, auction houses, etc. There were 10 things, if I remember correctly, that factor into how "classic" a car could be. They included things like

- Cultural importance: Did the car feature prominently in any movies (i.e. Jag E-type, Mini in the original Italian Job or Mustang in Bullitt)
- Racing heritage: was the car raced? Think of those grainy black and white photos of the Gullwing Benz
- Technical significance: The primary reason everyone wants a 959, for example
- Must have a prestige badge: ANY Ferrari has collector appeal because of it
- Exclusivity: Simple economics here. Tight supply drives up the price (if everyone wants one).
- Beautiful/timeless styling: 1964 1/2 Mustang. Sixties Buick Riviera. Studebaker Starliner coupe. All still imitated to this day.

There were others, but I can't remember them right now. Maybe one of these days, I will dig up the magazine and plagiarize it a bit further. By most measures (styling aside), the Crossfire is set for somewhat meager collectibility. Sure, it's beautiful. But, it breaks no new ground technically, has no racing heritage, is not particularly rare with more than 60K built, does not feature prominently in any movies or songs, and does not offer prestige in the league of the most sought after luxury or sports cars. In fact, with its retractable roof, an identical platform, a starring role in several travel memoirs, and the Mercedes badge on its snout, the similar (old) SLK stands a far better chance of being a collectible some day. Look at used SLK prices versus used Crossfire prices, calculate the percent depreciation, and you'll see what I mean. The SLK's already have a start on us.