From the listing for this Porsche Le Mans Race Car for sale:

One of 46 of these cars produced by Porsche, 0145 was a ‘Werks’ car that competed at four world championship events during the 1958 season. During this time it notably achieved two class wins, at the Nurburgring 1000km and the Goodwood Tourist Trophy. The car also holds the accolade of being the only 5550A to contest a Formula One race, competing at the Dutch Grand Prix held at Zandvort in the same year. Leading historic Porsche expert, Andy Prill of Maxted-Page & Prill, stated that this car, in respect of all 46 550A Spyders ever produced, ‘truly ranks in the top three cars with the racing heritage and history it has accomplished.’

Famously described by James Dean as ‘The Giant Killer’, Porsche’s 550A Spyder proved that a small engine in a lightweight car could achieve far more than just class wins. On the right circuits and in the right conditions these remarkable little cars could and did achieve outright success. Chassis 0145 is living proof of this fact, having achieved fifth place overall at the Le Mans 24 Hours in 1958 under the racing number ‘32’; the best-ever result at Circuit de la Sarthe for a 550A Spyder.

From Wikipedia:

The first three hand built prototypes came in a coupe with a removable hardtop. The first (550-03) raced as a roadster at the Nurburgring Eifel Race in May 1953 winning its first race. Over the next couple of years, The Werks Porsche team evolved and raced the 550 with outstanding success and was recognized wherever it appeared. The Werks cars were provided with differently painted tail fins to aid recognition from the pits. Hans Herrmann’s particularly famous ‘red-tail’ car No 41 went from victory to victory. Porsche was the first car manufacturer to get race sponsorship which was through Fletcher Aviation, who Porsche was working with to design a light aircraft engine and then later adding Telefunken and Castrol.

The Porsche 550 Spyder became an active participant around the European and US championship circuit between 1953 and as late as 1965 starting in over 370 races. With approximately 95 overall wins along with an additional 75 class wins, the Spyder dominated against more powerful cars not even in its class. With a mix of international drivers from Jack McAfee, Ken Miles and Wolfgang Seidel to legends such as Huschke von Hanstein, Helmut Glöckler, Hans Herrmann and Richard von Frankenberg, the Spyder was well represented at famous circuits around the world. From the tracks of Avus, Nürburgring, Le Mans and the Targa Florio in Europe to the more active competitive circuits found in the US at Sebring, Palm Springs and Lime Rock, the Spyder which became the race car of choice for privateers, soon earned the reputation as the ‘Giant Killer’.

The later 1956 evolution version of the model, the 550A, which had a lighter and more rigid spaceframe chassis, gave Porsche its first overall win in a major sports car racing event, the 1956 Targa Florio.