So, no need to give the new A4 a significantly different character. But there were areas in the 80 that were definitely in want of improvement. It was too heavy, and in consequence too slow; the cheaper versions had dated, wheezy engines; and the suspension could be surprisingly uncouth.
Last year, the company gave Mercedes, Jaguar and BMW a rude shock: the Audi A8, a £47,000 range-topper that is as desirable as any big saloon from those eminent stables. If much of the large A8's magic could rub off on the small A4, its success was assured.
For the A4, the engineers came up with a body that is muscular yet elegant, and distinctive without being flash. Inside, you couldn't be in anything other than an Audi: the company's interior design team, led by the Englishman Martin Smith, is one of the best around. Shapes and textures are restrained without being drab; the instruments are clear and plentiful; the seat and steering wheel adjust to suit everyone and there's plenty of storage for knick-knacks.
Every lever and button operates with a pleasing precision. If you're looking to find fault, the centre console is overcrowded with rows of confusing buttons, especially if the optional climate control system is fitted.
While the A4 is no bigger overall than the 80 (and it is a little lighter, too), there's welcome extra room in the back seat. Don't imagine it to be as spacious as family holdalls such as the Ford Mondeo or Citron Xantia, but a group of four should certainly be able to fit themselves in comfortably. An eight-hour shift at the wheel left my bones untroubled by aches.
In response to market pressure and better crash-testing, all new cars are improving in their ability to protect occupants, and a good look at the design and specification (I refrained from crashing it) indicates that the A4 is among the leaders.
The A4's most intriguing feature is one of its engine choices, a 1.8- litre turbo. This has only four cylinders (not a recipe for the smoothest operation when rivals have V6s) but every cylinder breathes through not two, not four, but five valves. This layout is chosen to promote economy, low-speed responsiveness and clean exhaust emissions.
Together with the turbocharger, the effect is simple. When you open the accelerator, a lot of air can be crammed into the cylinders, so there's a strong flow of power. But because the engine displaces only 1.8 litres, when you aren't running at full
throttle, it's economical. Another fine characteristic of the new turbo engine is that there's no "kick point" where the power arrives with a whoosh - delivery in the A4 turbo is well- mannered as well as hearty.
Having replaced the old Eighties lacklustre power-unit, the next item on the to-do list was the suspension. Each front wheel is now held in shape by a complex quartet of arms, and the result is that the A4 is highly resistant to being knocked off course by bumps, and rides serenely into the bargain - both of which are gratifying improvements on the 80. It can also generate great cornering forces with very little drama, tracking neatly around a bend even if you've been clumsy with the accelerator.
The A4 moves down the road in a considered sort of way, responding to your bidding precisely but with a certain deliberation. Most drivers will get on well with it because it's never nervous. But there will be others, trading up from hot little Peugeots, say, or devotees of the BMW 3-series, who will find that it doesn't quite have the agility or exhilarating reflexes they crave.
Yet for most tastes, the A4 is a terrific car. Although by no means a cheap one, it is a mechanism of such poise and polish that if you have the money to spend, you'd be satisfied spending it here.
Audi A4 1.8T, £19,370 Engine: 1781cc, four cylinder, 20 valves, 150bhp at 5700rpm. Transmission: five-speed manual, front-wheel drive. Performance 139mph, 0-60mph in 8.0sec.
BMW 320i, £19,310 More agile than the Audi but less relaxing, since the engine needs to be wrung hard. Cramped in the back seat, but for the driver it's an inspirational car.
Ford Mondeo 24V Ghia, £20,175
The best mass-market challenger. Excellent driver's car, also comfortable and generously equipped. The problems are visual: it's bland outside, rather tarty within.
Mazda Xedos 6, £18,895
Delightful quirky looks backed up by a well-equipped and quiet cabin. On bendy roads, it's outclassed by its rivals.
Mercedes C200 Esprit, £19,960
Marvellously engineered, safe, durable and excellent for long motorway hauls; the downside is that it's spartan and feels slow.
Saab 900 2.3S, £18,485
Roomy Swede is safe, relaxing, and, thanks to five-door layout, practical. Less polished than the Audi, though.
Rover 623 SLi, £18,995
Agile handling and nippy engine go well with the Rover's smartly veneered cabin, but jittery ride lets it down.