According to Gooding and Company, "between 1970 and 1972, Porsche built a limited number of sport-purpose 911's that are now commonly referred to as ST's – referring to a 911 S in the lightweight trim of a T. Following the tradition established by the 911 R, these 911 STs were purpose-built competition machines developed at the pinnacle of Porsche’s endurance racing program and equipped with state-of-the-art components. Constructed in Porsche’s Werk I race shop, STs were campaigned by privateers and the factory team in a wide range of events – from endurance races to punishing, off-road rallies." Reportedly, a total of 49 samples were built by the factory for different racing needs. Given their rarity and heritage, the few remaining 911 ST's are highly sought after by collectors today.