Seems to me that it's probably worth the incremental cost to buy one that's already here and registered in your state; there's a lot of unknowns in customs and vehicle licensing, and I'd rather not deal with it. But I spent my weird car slot on a 1981 Vanagon instead of a kei truck/van.

Based on what I’ve seen from states that are attempting to implement new rules, Kei trucks and cars aren’t grandfathered in, sadly.

Even buying one locally that is already registered doesn’t guarantee that you’ll be able to continue registering it.