Indeed it is and with a suitable 2L motor, such as the Mazda one, they could offer the Plus 4.
BUT are the cars "52 State Legal", or do some States not recognise the CA "kit" car exemption?
The general rule of thumb is that if you can title it in California(home of some of the most strict and erroneous road tax/title laws in the USA) you can title it anywhere. That's in stark contrast to FL where I can title practically anything with wheels that will move under its own power. I even managed to title an old 8hp lawn mower once on a whim...it's now road legal and perfectly capable of cruising on the local motorways at an astonishingly fast 13mph.
