tonytodd - here's a couple of great sites that outlined some costs associated with building a FFR - again just to give you an idea.
Cost of Building a Factory Five with new parts
FFCobra Survey Results
John's FFR build site
Even an ERA which starts at around 17.9k to start and with up at around 47.2K with "standard" options ends (at least for me) and that's just to the parts - doesn't include putting the putting together "stuff"....
Might want to look at completed used Cobras from owners - they normally represent the best bang for the buck....
my humble .02 cents.