I agree with Chuckdoc. Also, as a collector, I would put my money heavily on the current generation of Saleen products being more valuable and more coveted than the GT500 30 years from now..
We've discussed this on other threads. If you really think about it, and if you know your car history, the Saleen Mustangs are MORE LIKE the original 65-70 Shelbys in provenence, rarity, execution, separation in styling, than the damn new Shelby is.
Steve Saleen, ex-race driver turned car builder, taking Mustangs from Ford and modifying them, and then selling them as new cars through specified Ford dealers. They are numbered, serialized, and relatively rare. They are also very-much visually modified and separated from the regular Mustang line both inside and out. Multiple product lines offering different levels of price/performance. And an uber-expensive halo car in the S7 which is a winning race car.
Kind a sounds a bit like what Carroll Shelby did in the 60's, doesn't it??
The new GT500 is a Shelby-badged SVT product sold at all Ford dealers. Other than the nose and the wheels, it really doesn't have that much going on visually to set it apart from a GT. Yes, you could argue that the 68-70 Shelbys were pretty much Ford products, but AT LEAST they still carried that extremely unique bodywork, especially 69-70, where they stood on their own and could not be mistaken for being "just a Mustang with stripes".
I think that Shelby is a legend and an icon, and that values for the 1965-1970 cars will always be stratospheric as a result.
I think that Saleen is not near the legend or icon, but that his CARS made a bigger statement than Shelby's did in the '60's. Saleens Mustangs won more championships, and Saleens Mustangs carried the same panache in their day as the '60's Shelby Mustangs did, if not more.. (Shelby never built totally NASTY stuff like the supercharged S351's or the Extremes, at least not any more than on a onesy-twosy basis for himself and close friends...)
Down the road, Shelby will be the legend, his Mustangs from the 60's will be as well. But in the world of MODERN 3rd-4th-5th gen Mustangs, the Saleens will occupy the top rung...
And yes, with the 5.4, the GT500 does have the "potential" to be nasty-fast with mods. At the end of the day, that doesn't really carry the entire collectible story... The 1968 GT500KR was typically loaded-up, option-laden, and not as fast as a cheaper stripped-down 68 1/2 GT 428CJ. But put those two cars on the option block, and you'll quickly see that faster doesn't mean more valuable.