The 250S was developed in response to Ferrari's 500 Mondial which featured a four-cylinder engine and was quite successful in sports car racing.

The 200S debuted at the 1955 Imola Grand Prix, driven Franco Bordoni, but yielded disappointing results.

Both cars were forced to retire, with Maserati winning the race with a A6GCS driven by Francesco Giardini.

Problems with the suspension would be resolved by fitting two cars with a De Dion tube attached to the differential with a sliding pin at the rear.

The SI featured a wider windscreen, wipers, doors and a perfunctory hood capable of keeping the rain out only when the car was parked rather than protecting the driver from the elements during a race.