bodywork was originally entirely made of glass-reinforced plastic (GRP), allowing a very light weight of . This lasted until June 1977, when the 308 was switched to steel bodies, resulting in an overall weight increase of approximately . Five-spoke 14-inch alloy wheels were standard, while 16-inch wheels were made available later as an option together with sports exhaust system, high compression pistons, a high lift camshaft and a deeper front spoiler. At the 1977 Frankfurt Motor Show, the targa topped 308 GTS was introduced. All GTS' received a wet sump engine and were steel-bodied. European GTB models retained the dry sump lubrication until 1981. There were 3219 GTS' and 2897 GTBs made from 1975 to 1980. Only 808 of the fibreglass (vetroresina in Italian) version were made, all with the Berlinetta bodywork. 308 GTBi/GTSi In 1980 Bosch K-Jetronic mechanical fuel injection was offered, leading to the 308 GTBi and GTSi; emissions decreased, at the price of a power drop to on European models and on federalized models. The fuel injection was coupled to a Marelli MED 803A Digiplex electronic ignition, incorporating a coil, distributor, and ignition module for each bank of cylinders. Outside, the car was identical to the 308 GTB/GTS, save for metric sized wheels of a slightly different design, fitted with Michelin TRX radial tyres—Michelin XWX on 16-inch wheels were optional. Inside, the clock and oil temperature gauge were moved to the centre console; there were also a new black steering wheel with three perforated spokes, and seats of a different pattern. 494 GTBis and 1743 GTSis were produced before the model was succeeded by the 308 Quattrovalvole in 1982. 308 GTB/GTS Quattrovalvole Two years later, at the 1982 Paris Motor Show, Ferrari launched the 308 quattrovalvole, in GTB and GTS form. The main change from the 308 GTBi/GTSi it succeeded were the four valves per cylinder—hence its name, quattrovalvole, literally "four valves" in Italian—which pushed output back up to restoring some of the performance lost to the emission control equipment. The new model could be recognized by the addition of a slim louvred panel in the front lid to aid radiator exhaust air exit, power operated mirrors carrying a small enamel Ferrari badge, a redesigned radiator grille with rectangular driving lights on each side, and rectangular (in place of round) side repeaters. The interior also received some minor updates, such as a satin black three spoke steering