Hi Ryan,
I understand your situation, there's a lot of really good mass produced cars out there for 70,000 or less, used. Vettes, Porsches, Mercedes, unfortunately NO GT40 replicas of high specification. A well sorted CAV, SPF, ERA, RCR will drive extremely well and actually feel like a production vehicle in terms of stability and road manners. But this comes at a price.
You can buy GT40s with tube chassis (not monocoque), Getrag or Renault transaxles and a fairly tame 302 engine occasionally under 70k, however it's fair to say that anyone who owns a car like this, that is well sorted, will not part with it for under 70K either.
Why is that? Because whether it's a monocoque or tube car, monster motor or stock, Getrag or ZF, Webers or 4bbl, you simply can't buy the parts to build a running GT40 for 50k, sorry can't be done. Add to that the assembly and some professional assistance (you'll need it) plus paint and your well over 70k doing it mostly yourself. That's a modest spec car too.
As has been mentioned earlier, the SPF cars popping up for sale right now are absolute bargains, get one while you can. Once this batch of loose cars are gone, the market will go up, that's not speculation or manipulation just the reality of what these cars cost to build. I don't doubt for a minute there's 143k in the SPF GT40Mk11 in question.
When seriously considering a GT40 replica, you're looking at a legitimate 200mph car, not a dune buggy or Cobra built with a Mustang donor drivetrain and suspension. Just two headlights and a windsheild for the GT40 cost more than a transmission for the Mustang.
So these really aren't kits in the classic sense of the word, rather component race cars that you decide on the specs for, build yourself or have built, or buy the best you can.
Forget everything you know about kit cars, doesn't apply here. On the plus side, there are good project cars out there you could start a build on and ulitmately end up with the car of your dreams, one you won't see twelve more of at the local car show and something that will retain it's value for years to come (vs production car depreciation).
Please hang in there, GT40s are only for the guys who really appreciate the machinery and want a unique and significant car. The GT40s Forum is chock full of members who'll help out a newbie on any build issue that comes along, welcome aboard.
Cheers
Ian