Audi released the C4 in late 1990 in Continental Europe and during 1991 in other markets, including the right-hand drive British market.[54] It was a rebodied and updated C3, keeping the chassis, suspension, and most powertrains. The most significant menchanical changes were the new V6 engines and a wider track, increased by 4–5 cm (1.6–2.0 in) front and rear.[55] The C3-platform Audi V8 continued to be sold as a separate line. The major change for the C4 was the introduction of a 2.8 L, 90-degree, SOHC 12v, V6 engine. It was later joined by a 2.6 L variant, of the same configuration as the 2.8 L unit. They are essentially the same engines offered in the 1992, B4 Audi 80. The option of quattro permanent four-wheel drive was an option across the range, except the smallest engines. The Audi 100 quattro was available with a ZF four-speed automatic and a 5 speed manual gearbox. This generation was also available with the 2.5 litre, 5-cylinder TDI engine, introduced late in the C3 production, which provided outstanding performance, economy and refinement. During 1994, in conjunction with some styling revisions, Audi dropped the Audi 100 tag, renaming it the A6 instead. In addition, the existing 100-derived Audi S4 became the S6. The S4 name was later reused for the high-performance derivative of the Audi A4(replacement for the Audi 80). The Audi V8 had been replaced by the A8 in 1994. The C4-based A6 continued until early 1998, when it was replaced by an all-new A6.