It is an extremely rare sight when you see a BMW Z1 in the US (only 8000 were produced for Europe). They were not sold here and would have to pass DOT, EPA and other requirements to be imported; usually an expensive task.
Apparently, the seller has a “Show or Display ” waiver allowing 2500 miles per year and the right to be US legal. You can see more of it over at Bring a Trailer; oh and the asking price is $39,500 on Ebay. Thanks Mark for the tip!