Newer lower production porsches like the gt3 rs and the like sell for more since demand outweighs production, making them instantly collectible buy them will tell if that will remain the case. For instance, priuses back in 2009 were selling used for more than new, and I wouldn't call them collectible now. If the gt3rs turns out to have some fatal flaw that puts them out of favor with consumers like a baby cries every time you hit the gas then it may also not be collectible.
Further, the car may not be back at msrp, but it's also relative to when you bought it, if you bought it now then you have an appreciating asset, thus adding to the collectibilits of them now.

 

Historically, colors, even rare ones, don't usually jump a price of an otherwise normal car to a more rare car, but a desireable color does make it alot easier to sell. A white cr may be the unicorn in 30 yeara.

 

A well maintained and lower mileage S2000 won't be dropping in value anymore. That makes it collectible to me. Pretty cool to have a nice car in the garage and not lose any money on it.

 

A GPW CR in excellent condition with low low miles is worth 37k to the right buyer...and Im the right buyer That ITR going for $34k is completely nuts to me...but I can understand the love for them.