MONTEREY, CALIF. — On August 16 at the Monterey Conference Center, RM Sotheby’s sold the 1994 McLaren F1 “LM-Specification,” the world’s most revered modern supercar, for $19.8 million, including premium, becoming the most valuable McLaren ever sold at auction.

The world’s fastest naturally aspirated production car, serial no. 018 is one of just two upgraded to Le Mans specification by McLaren, equipped with the GTR engine and an extra high-downforce package that went above and beyond the coachwork effects of the original five LM cars. Used on a handful of tours and rallies, the fastidiously cared-for McLaren was offered at the auction showing just 21,500 kilometers, the best imaginable iteration of an already perfect machine. With the crowd on their feet as the car drove onto the auction podium, four bidders vied for 4½ minutes before the car sold to a private collector based in the United States.

The August 17 session headlined by the presentation of the 1939 Porsche Type 64, the antecedent of the Porsche brand, was marred by a technical error that caused the oldest car to wear the Porsche badge fail to sell at auction. The error caused the bidding to be halted at $17 million, below the reserve price — or minimum required by the seller — so RM Sotheby’s pulled the lot.

“The car didn’t meet reserve,” RM Sotheby’s said in a brief statement. “We will make every effort to sell the car postsale.”