Sauber’s Group 5 M1. Sole-surviving fully-restored twin-turbo racer profiled. One of a Kind When Sauber wanted to race the M1 in Group 5 it built two from the ground up. There’s just one left. Back in the 1980s Sauber built two Group 5 twin-turbo M1s from scratch and this one is the only surviving example. Words: Robb Pritchard. Photography: Wolfgang Maringer.