To title/register my newly built Cobra in Colorado, my first step was filling out some paperwork with the DMV (the large main DMV office in Lakewood off Pierce; the wait wasn't only a couple minutes for title/registration).
A few weeks later, the DMV had approved the documentation and gave me instructions to schedule an appointment with the Colorado State Patrol so that they could attach a Colorado-assigned VIN plate on the car. The Shell Valley VIN number isn't enough; it has to be a Colorado-assigned number.
So a week later, the DMV gave me a temporary permit to drive the car. I drove the car to the Colorado State Patrol in Golden. Pulled up. No questions asked. The officer had me pop the hood and he put a VIN plate on the frame. Next, he gave me documentation to take back to the DMV to show the new VIN plate had been applied.
Another month or so later, the DMV let me know that everything had been approved and title/registration was now possible. I went to the DMV at the Jefferson County Office building. No wait. The clerk knew no emissions test was required for a kit car, so everything was able to proceed immediately. He gave me my plate.
It was a long process over a few months, so I am probably missing some details in there.
There's also an overview of the Colorado title/registration process posted at:
Mile Hi Cobra Club : Ask Dr. Cobra
However, when I took that list of steps to the DMV, along with those form numbers, the DMV said it was wrong and gave me different instructions/forms.
I'm just glad I started all this at the beginning of winter so the car would be ready to go by spring!