The answer about registration and smog
are related. If you register the vehicle
as a new car, you're pretty much stuck with
current emmission levels, and will have to
run with injection/cat converters.
If you register the vehicle as a mid-sixties
car (like the Cobra guys) the levels are
easy to make, and the car may even be
exempt. You may want to talk to someone
who builds kits in Colorado, like T-3 or
Melson.
MikeDD