Mike, I just wrote a big post explaining everything in detail, it is very complex. When I posted it, I had timed out and it was lost, thanks a lot Theron.
Anyway, here is the short answer, CA Veh Code 580. If the car does not resemble the car from which its parts were derived in its construction, it is a Specially Constructed Vehicle.
My point on Mr. Morgester's presentation is not specific to Speedster's. The state is becoming aware of our existence for various reasons, unfortunately it seems, most of the different departments, much at the same time.
My recommendation is simple: If you live in CA and have a Replica or a Hot-Rod (at least one that does not resemble to a fairly large degree the car it was derived from), register it as a Specially Constructed Vehicle, declare its full value when you register it, get an SB100 SMOG exemption if you can and if you can't, get it SMOG compliant for the year of the engine that is in it. If you do this, you are legal, if not, well...
In all my many years, I have learned one thing about the Government. The wheels grind slowly, but eventually, they will catch up to you, if you are not 100% legal, they grind right over you.