Matt Kimberley, PA motoring writer, says Audi's A4 just gets better and better if you want a fuss-free compact executive car.

Some things in life never change, and after more than 30 years it seems like the Audi A4 might be one of them. Thankfully things aren't always as they seem, and the game has moved on a bit.

Rather a lot actually, as the stats show. Since 2000, which accounts for the last four models including the new one, the A4 has gained power, torque and just a little weight, while shedding big numbers from its fuel consumption and CO2 output. It's even a little faster than it used to be.

It would be remiss to suggest it's purely money that has greased the wheels of change. It's true major investment has been made as a result of EU demands for greater efficiency, lower emissions and other vote-winning ideas that as a happy by-product tend to leave the average consumer with more spare cash.

But Audi is a company driven by the desire to be the best at building luxury cars for the masses. It has defined what it believes a great luxury car should be – a set of rules it's sticking to. That's partly why the A4 has barely seemed to change down the years, while actually changing a lot where it matters.

Subtle styling updates have simplified and sharpened the front end, away from the blockishness that has been a mainstay of German design over the last five years or so. It's prettier than the old one, even if it's not especially daring or racy.

The more significant changes are under the skin, with a series of impressive redeveloped and new engines. Company-car drivers and their fleet managers are under more pressure than ever to reduce costs, so Audi has delivered CO2 output figures as low as 112g/km, and 65mpg potential fuel economy.

Six TDI turbo diesel options join two turbocharged petrols, with two of the diesels earning Audi's special TDIe designation reserved for its most frugal cars. They are 134bhp and 175bhp units respectively, but there's actually relatively little to choose between them on the road or even on paper, where the more powerful engine is almost as efficient as the entry-level one.

The most remarkable thing about these new diesels is how smooth they are, especially at low revs. Reducing cruising revs helps boost fuel economy, and the new breed of common rail motors are happy to be driven down to just 1,000rpm, while still picking up smoothly.

While the 134bhp TDIe, likely to be the best seller, is happy to trundle about just over tickover using its long gearing, it does need a good handful of revs to extract the performance on offer. Fortunately the engine has no problem with that. It feels almost like a petrol in a way – and that's high praise.

Then there's the issue of noise. Inside the new A4, there isn't much of it. Even at motorway speeds, noise is staggeringly well hushed. Roar from the rear wheels is more obvious from the rear seats, but it won't bother the driver.

A4s have not been blessed with the best ride quality in recent years, partially thanks to very stiff chassis and bodies. The new one isn't bad, but it does benefit from being fitted with the basic 17in wheels. Top-of-the-range model's lowered sports suspension and 19in rims, although they look mighty fine, might be an issue on broken British roads.

Interior quality is as high as ever. It feels like some materials have been lightened over the generations, but it's still solid and stylish, and the doors shut with a satisfying thunk. The exceptions are the various wood trim inserts that don't look quite right, the cheaper silver-grey textured plastic ones look better.

The A4 is a very fine car to drive. It has a long wheelbase which helps make it feel stable at a cruise, and there is plenty of grip from wide tyres on all models. It follows the pattern set by previous A4s in that it's very good at satisfying owners without being overbearing.

It's not what you'd call inspiring or breathtaking, but it's not meant to be. It's designed to be a fuss-free luxury compact executive car that people will be happy to see on their drive. An Audi is a car that doesn't need any explanation. The A4 is a brand in itself and with better engines than ever, its appeal has redoubled.