Back in the archives and annals of Club Cobra there was a gentleman by the name of "rsimones." He had a Corvette, bought a Cobra and the sold the Cobra and bought another Vette. He was not prepared for Cobra ownership and I think you should think long and hard about buying a Cobra, because they are a very different "animal" than the cars that you currently own.
I used to own a 1966 427 Corvette Convertible with a 540ci engine and sidepipes. A WAY different experience. Also I think they made too many special edition Z06's in 2004 for them to become valuable. I think the ERA will hold its value better now that whoever buys this car won't be the original owner and/or builder.
EDIT: Added link to old "rsimones" thread, though it has been "neutered" by the OP before he left CC.
New to the Cobra world? Have you always dreamed of having a Cobra? Read carefully.