From 1977, all 308 bodies were made of steel with aluminium doors. In September, at the IAA Frankfurt Motor Show, the 308 GTS convertible was launched, filling the gap left 3 years earlier by the discontinuation of the 246 GTS. Pininfarina used the same principle of a removable roof that stows away behind the seats. The only difference with the GTBs was that the rear quarter windows were replaced by metal fins, which still provided side visibility. The abandonment of polyester shells is certainly justified in these new GTSs, whose rigidity would then have been insufficient. The men from Maranello certainly thought it more logical to standardise the hulls.