People figure out ways to get around everything here, it may not be legal, but most don't care. People have tried putting them on the road as kit cars, others are for track use only and drive it on the roads anyway. What you see the most of here is people getting a 240sx shell and pulling the vin number off the dash and the firewall and scrapping the car. They put the vins on the imported car and there is really not a way to catch it. There was a scare about 6 months ago where some grey market imported cars were being confiscated and crushed. LOL there were skylines everywhere on the east coast going up for sale. Motorex actually got r33's legal, but they got busted bringing in r32's and had a multi-million dollar lawsuit pressed on them. The r32's they brought in were allowed to stay here under a grandfather clause so those are safe here.
As for mazworx, if your talking about the green s15 they have there would be no way to make it legal. It has a tube chassis, airbags or anything safety wise. But, then again if they knew the right people they could get by with it. (as in paying the inspectors off)