The regulations for the GT1 class at the time mandated a limited run of homologated street versions, and that's what you see here. Called the Straßenversion (that antiquated ß character in the German alphabet substituting for a double S), only 25 examples were made, and one's up for sale.
As a street-legal road car, the 911 GT1 Straßenversion followed the 959 and preceded the Carrera GT at the top of Porsche's lineup. While most were fitted with a version of the competition-spec 3.2-liter flat six with 536 horsepower, the seller of this particular example says his has been re-tuned to 690 hp. The car's asking price is €1.2 million (about $1.7 million), and it's currently located in Japan.