Originally this numbering convention ran concurrently with that of the Volkswagen Passat, the first generation of which was essentially a badge engineered clone of the Audi 80.

The Audi F103 series, based on the DKW F102 but with an all-new range of four-stroke engines developed in conjunction with Daimler-Benz, was sold between 1965 and 1972.

It effectively took the place of several models that Audi had discontinued (the F103 series, which included the first model designated as an "Audi 80"), and provided the company with a viable rival to the Opel Ascona and the Ford Taunus (Ford Cortina in the UK), as well as more upmarket offerings including the Alfa Romeo Alfetta and Triumph Dolomite.

In September 1973, Audi added the sporty 80 GT (two-door only) featuring a carburettor 1.6-litre engine (code: XX) rated at 100 PS (74 kW; 99 bhp).

The Audi 80 had a MacPherson strut front suspension, and a C-section beam rear axle located by trailing arms and a Panhard rod, and using coil springs and telescopic dampers.

[3] Audi's design and development efforts paid off during the 1973 European Car of the Year competition where the 80 won ahead of the Renault 5 and the Alfa Romeo Alfetta.

[4] The Fox originally had a 1.5 litre engine rated at 55 hp (41 kW; 56 PS), attached to a four-speed manual transmission.

Audi presented a redesigned 80 based on the B2 platform (Typ 81) in September 1978 and deliveries of the four-door sedan began a few weeks later in Europe.

No Avant variant was available, as the Volkswagen Passat filled that role, as the B2 was intended to move the 80 upmarket from the mid-sized family segment to a compact executive model pitched to rival the BMW 3 Series.

[16] The saloons were offered until late 1986 in Europe and 1987 abroad, and the B2-based Audi Coupé lasted through to 1988 (as an early 1989 model) before being changed.

The 5+5 was essentially an 80 B2 two-door saloon with the 100 hp (101 PS; 75 kW) 2144 cc five-cylinder engine from the 5000 and a five-speed transmission.

It was fitted with various sporty parts such as an oil pressure gauge, sports interior, and alloy wheels as standard equipment.

The Audi 4000 quattro debuted in 1984 and was sold in four colors, Black, Alpine White, Tornado Red, and optional Zermatt Silver metallic.

The mounting for the safety bumpers intruded into the luggage compartment floor, making for a very irregularly shaped and less useful space.

The CS quattro has a CIS-E fuel-injected 2.2-litre inline-five cylinder petrol engine (identification code: JT).

A range of new petrol and diesel inline four-cylinder engines became available to European customers along with the procon-ten safety system which became standard fitment from 1991.

Procon-ten was a notable safety feature comprising a series of hidden steel cables routed behind the gearbox, attached to the steering wheel and front seatbelt inertia reels.

This action simultaneously pulls the steering wheel into the dashboard to prevent the driver colliding with it while tightening the front seatbelts.

[27] Externally, Sport versions of the 90 were visually distinguished by the deletion of brightwork in favour of satin black window surrounds, bumper cappings, and thinner side mouldings.

Changes from the B3 included a longer wheelbase, a fully redesigned fuel tank and rear axle to enable the use of folding seats, 15" wheels with more prominent wheel arches, redesigned and painted rear and front bumpers, as well as higher-quality materials for the interior, and a larger boot.

The B4 also marked the beginning of Audi's move into the German luxury mid-sized vehicle segment, which until then was clearly dominated by Mercedes-Benz and BMW.

B4s for the American market typically offered more luxury and style even in the standard version, such as automatic transmission, cruise control, air conditioning, and leather seats, all of which were usually optional at additional cost on European models.

Instead of the dual-reflector headlamps, a single-reflector design was used inboard of an amber combination turn signal, parking, and side marker lamp and reflector wrapping around the corner, and fog lamps smaller than the rest-of-world items were placed the corners of the bumper air duct.

It was a street homologation of the B4-based Super Tourenwagen Cup (STW) race car saloon with four-wheel drive and a modified 140 PS (138 hp; 103 kW), 16-valve, two-litre petrol engine.

For the North American market, however, Audi only sold coupés during the 1990 and 1991 model years, and the station wagon was never officially available.

In 1993, the S2 received some cosmetic updates, including new AVUS-style alloy wheels, ellipsoid beam (projector) headlamps, and clear front indicator lenses.

The Audi RS2 was generally only available as an Avant, although four 4-door saloon models were officially produced by the factory, including one for the chief of the RS2 development programme.

Prior to manufacturing the RS2, the Porsche Zuffenhausen assembly line was busy producing the high-performance W124 bodystyle Mercedes-Benz 500E.

Additionally, the word "PORSCHE" is inscribed in the RS2 factory emblems affixed to the tailgate and front grille, and on the engine's inlet manifold.

Porsche modified the Avant S2 body optics, added more power, better brakes, bigger anti-roll bars to front and rear, fine tuned the interior – and a super-sports estate was born.