This isn't intended only for this post, but also for the other current post comparing GT/CS with shelby.
Why would anyone want their GT/CS signed by shelby? It isn't a shelby. Just because some shelby fiberglass was thrown on it doesn't make it a shelby.
Sure, it may have had influence from shelby, but that could be said for any mustang that may bear any influence such as newer mustangs bearing the name Cobra. Are they shelbys? I say no.
I think a line of definite distinction should be drawn between the shelby mustangs and the gt/cs mustangs. As hard as a gt/cs owner may wish, their car is as much a shelby as a mexican toyota camry sporting shelby racing stripes.
I really don't think adding shelby's signature to the car adds any value at all (as measured in dollars, not sentiment), in fact, it might take some value away from the car because it shows the potential purchaser that the previous owners aspirations for the car are unattainable and somewhat lofty.