For the 1956 season, the much improved 550A/1500RS was introduced. Better known as the '550 RS' in the U.S., it's visually similar to the 550 spyder but the chassis underneath is completely new. It now has a tube frame structure designed to dramatically reduce the torsional flexibility. At the same time, the rear suspension was completely revamped, although still a swing arm design, an anti-roll mechanism was added, improving the grip of the rear end under cornering. Finally, the 4-cam engines performance were significantly enhanced with crankshaft mounted distributors, higher compression, and new Weber carburetors, good for 23 more HP than the original 547 engine.

In the second race of the season, the 1,000 km of Nurburgring, S/N 0101 finished first in class and fourth overall, driven by Wolfgang von Trips and Umberto Maglioli.

A few weeks later, a works 550A single-handedly driven for more than 7 hours by Maglioli won the Targa Florio, beating all the Ferrari and Maserati entries, it was Porsche greatest victory to date at the time.

More importantly, the 550A proved that Porsche's concept of small engine in a lightweight car could do much better than class wins, and in fact, on certain tracks these remarkable little cars were more than capable of winning overall.