 Complete the following phrase:  Maserati A6GCM 195153 were twelve 2-litre single-seater M for monoposto racing cars 160-190 bhp, developed by Gioacchino Colombo and built by Medardo Fantuzzi. The A6 SSG 1953 was a GCM-revision pointing to the Maserati 250F. It won the 