Those advising you to get to know your local Cobra club members, talk with them and become familiar with the major brands of replicas are spot on.
Other than the fact that they're all a bit different, there are other factors that will affect the medium to long term appreciation and enjoyment of the replica you choose and buy.
The issue of
authenticity to the original is a big factor in the amount of "respect" (which influences market value) a Cobra gets among aficionados and enthusiasts. If you just want a Cobra-like hot rod to blast around in, that may not matter, but if you are becoming a Cobra enthusiast, you might place a higher value on authenticity, which will become more and more obvious to your eye as you learn more about the marque.
There are some brands that are known (and duly respected) for having accurately shaped bodies that sit with the "correct" low stance with wheels tucked sleekly under the wheel arches; and there are other brands that only vaguely resemble a Cobra with jacked-up rear ends and tires bulging out the sides, dual roll bars, plush cushy interiors and modern-trend paint jobs.
Except for the extreme variants, most of the general public won't spot the differences, but knowledgeable car (and Cobra) enthusiasts will. Many people who choose the more "interpreted" brands - like Backdraft for example - love them for what they are and don't care as much about originality.
A great example can be seen in this thread where an owner documents his custom build of a pretty spectacular and formidable Coyote-powered Backdraft:
Let me introduce BDR 1591 aka VMS Mayhem
Do a search here and read up on some of the ERA and other builds of some awesomely beautiful and impressively accurate Cobras that awe the faithful with their attention to detail and stunning finished appearance. Here is just one example:
First Pics of ERA #795
There are those and just about everything in between. Get to know the current major brands like Factory Five (FFR), Hurricane, Superformance, Unique and Backdraft as well as the premium pinnacle brands like Kirkham and Shelby.
Don't rush - take your time to decide where your heart lies in the broad spectrum of Cobra enthusiasm and if you even decide you still want one, then your decision will be that much more satisfying in the end.
All the best and keep us posted.