Audi seems to go from strength to strength with 21 models and going on for 190 variations spanning £13,420 for the A1 to more than £108,000 for the Ferrari alternative R8.

It’s a stunning range which Audi, with relentless energy, seems determined to expand.

In 2010 Audi recorded its best ever worldwide sales of 1,092,400, a 15 per cent improvement over 2009. In the UK, 99,828 Audi models found homes last year, a 9.5 per cent rise on 2009.

Audi is investing billions of pounds in new products. By 2015 the range will have expanded to 42. Recent additions, including the A1 subcompact and the A7 Sportback, will be joined by, among others, the new A6 Saloon and the Q3 compact SUV.

Tested here is another new version of the A5. Initially sold as a two-door coupe, the range has expanded to include a convertible, high-performance models and a four-door fastback.

Audi already has a compact saloon with the A4, but it’s a testament to its ability to target its models at specific profiles that the two cars happily coexist.

The company is clearly doing something right. This time it’s the turn of the A5 range, with a refresh programme spanning cosmetic, interior and mechanical improvements.

In the case of the A5 Coupe, the main focus has been the engine range. Lower fuel consumption and emissions do much to keep the car competitive in a world where economy and CO2 are often the driving factors.

A redesigned entry-level 1.8 TFSI petrol motor now boasts 170bhp (up by ten), the potential to achieve 49.6mpg and emit only 134g/km CO2.

As such, in a perfect example of downsizing it effectively replaces the A5‘s 180 horsepower 2.0-litre petrol motor. There have also been changes in the diesel line-up, with Audi’s familiar 2.7-litre unit now replaced by a 204bhp 3.0-litre motor promising 57.6mpg and just 129g/km CO2. Completing the changes is a reworked 177bhp 2.0-litre diesel with headline-grabbing 122g/km CO2 and 60.1mph figures. Even the flagship S5 hasn’t escaped, with its V8 petrol motor now swapped for a more frugal but no less capable forced-induction 3.0-litre V6. Fuel economy jumps to 34.9mpg while it’s also a fraction quicker to 62mph too.

Audi’s green zeal isn’t at the expense of driver enjoyment, though. Keen drivers can still enjoy switchable suspension, throttle and steering modes.

Out on the road and the A5 Coupe displays a level of refinement and competence that’s hard to match. In newly uprated 2.0 TDI guise, the car proves quick enough on the straight bits to make overtaking safe and packs enough low down torque to make light work of the urban crawl. Overall, it’s easy to see this car as a frugal urban tool during the week and a brisk grand tourer at weekends.

Move up to a car with Audi’s quattro all-wheel rive system and the subtle improvement in stability and the ease at which the car can change direction is noticeable. Based on the technology underpinning the RS5, it’s now more responsive to changes in road conditions, while an optional rear sport differential can be fine tuned for a more thrilling experience.

Although always a stylish car inside and out, the refresh programme for the A5 Coupe has also included a few enhancements. Tweaks to bumpers, bonnet and light clusters should help differentiate new from old, while inside the cabin there are changes to the design of the steering wheel, gear level, column stalks plus, minor controls plus a new trim and upholstery options.

Meanwhile, Audi is getting set to launch another new model, the Q3. It’s a sports utility vehicle which joins the Q7 and Q5 and it goes on sale in November.

Priced from £25,000, the Q3 combines the raised ride height, elevated position and all-terrain agility of a classic sport utility with city-friendly dimensions.