Mine was built from new, so in NYS, the custom home built vehicle was what was recommended to me and worked out fine. Really not too much fuss.
That said, if the vehicle has a title, registration, etc from another state, I’d be inclined to try registering it as a “regular” car, though Vlad’s point about OBDII could pose problems. I’m not familiar with those issues because the custom home builts are exempt.