Audi's A3 2.0 TDI is a highly accomplished car with a driving experience well balanced between comfort and sportiness and an engine producing performance and economy in generous quantities. Some will hanker after a more thrilling drive but for the average premium hatchback customer, the A3 will be pretty near the mark.

There are right times and there are wrong times for manufacturers to throw their hats into the ring with a new technology. Putting faith in the latest innovation before it's properly developed or while teething problems still persist can be a costly error but by the same token, failing to jump aboard a bandwagon that's going places fast can put you at a competitive disadvantage that's hard to make up. Audi made its judgment on common-rail diesel engines when they first started to emerge and decided to stick with the impressive direct injection units it already had. The time to switch was always likely to arrive however, and within the latest 2.0 TDI A3 models, there beats a common-rail heart.

The decision to stick with direct injection technology made by Audi and its Volkswagen Group paymasters can hardly be faulted. Their engineers had achieved high injection pressures with their TDI units of the day that produced performance and efficiency that put many common-rail injection engines to shame. The latest second-generation common-rail engines have come on quite a bit since then, however and when creating the latest facelifted A3, Audi obviously deemed that the time was right to make the switch.

There are a pair of 2.0-litre common-rail injection engines offered in the A3, along with the stalwart 1.9-litre unit that perseveres with direct injection at the base of the diesel range. At 138bhp and 168bhp, the power outputs mirror those of the A3's old 2.0-litre direct injection engines and the engines also retain the TDI moniker but rest assured that the differences are significant. Common-rail injection engines fire fuel into each cylinder from a shared (common) pipe (rail).

"The lag and lunge of the older Audi diesels is gone and the power is piled on quietly and smoothly for a far more relaxing drive.."

The pipe is pressurised at 1,800bar while allows extremely fine atomisation of the fuel and a highly efficient combustion process. The injectors in Audi's TDI unit are capable of injecting fuel up to five times per combustion cycle at precisely controlled quantities so exactly the right amount of fuel is burner to optimise performance. It's all clever stuff and the results include top notch refinement and a very smooth delivery of power without the sudden lunge of torque that can afflict less sophisticated oil-burners.

The 168bhp TDI engine in the A3 produces its maximum torque of 350Nm between 1,750rpm and 2,500rpm while the 138bhp option weight in a shade down with 320Nm through an identical rev band. Performance from 0-60mph is 8.9s in the less powerful car and a highly rapid 7.8s in the range-topper. Drive either engine back to back with the 1.9 TDI and their greater refinement is instantly apparent, as is the availability of acceleration through a greater span of the rev range. The A3's petrol engines of similar output are quieter but the common-rail diesels really shouldn't give cause for complaint. The A3 remains a very rewarding car to drive in a variety of different scenarios, there are sportier options out there if that's your thing but the A3 strikes a fine balance between eagerness and comfort.

The exterior of the latest A3 has been tweaked but not in such a radical way that it put the kibosh on the residual value of the previous model. The front wings and the grille are a little shapelier, the headlights are sharper-looking and the side repeaters are now incorporated into the door mirrors. Choose an S line variant and there are LED daytime running lights that ape the R8. The changes to the three-door car add 2.5cm to its length, while the five-door Sportback model's dimensions remain unchanged.

The interior has also come in for some treatment. Believe it or not, the previous A3 was just starting to look a little off the pace in this department. Even far more mundane cars like the Vauxhall Astra and the Fiat Bravo were beginning to show Audi the way forward in terms of materials quality. The latest A3 ups the ante with more aluminium design elements, revised switchgear, a better quality instrument cluster and a rethink for the upholstery choices. Quattro four wheel drive is of course offered on certain variants. The luggage compartment of the three-door car features 350/1,080 litres of fresh air with rear seats in place and then folded, just pipped by the 370/1,220 litres of the Sportback.

A3 customers choosing a 2.0-litre TDI engine can opt for the six-speed manual gearbox or six-speed dual clutch S-Tronic option. Go for the more powerful of the two engines and there's also the possibility of quattro four-wheel-drive and both engines come in three-door or Sportback bodystyles. The A3 is available in standard, SE, Sport or S-Line trim. Standard equipment includes electric windows, remote central locking, a CD stereo and electric door mirrors. Safety features run to twin front and curtain airbags, seatbelt pre-tensioners and five-point belts for all seats.

Many A3 buyers upgrade their cars to Sport and S line specifications, trim levels tweaked by the UK importers to include an upgraded sports suspension kit with modified spring and damper settings designed to improve ride comfort without compromising on agility. For around £1,500 over the cost of a Sport-trimmed model, the S line variants include full leather trim, 18-inch alloy wheels, S line badging, a more aggressive front and rear bumper design and a roof spoiler.

Running costs are the key to the 2.0-litre TDI A3 models and you have to admit they're pretty low for premium hatchbacks with this kind of performance. All of the latest A3 models feature aerodynamic modifications and other tweaks to help the cars achieve better environmental performance and these help the 138bhp TDI model return 55mpg with 134g/km emissions.

Smart customers have long known the secret to running an Audi A3. Whereas some are deterred by the asking price, the more salient number is the three-year cost per mile figure. This is where Audi exacts revenge on its lower-priced rivals. In boasting healthy residuals, the A3 drives down the total cost to the owner quite significantly. This does need to be balanced against the fact that you will be able to buy a bigger-engined rival for about the same running cost as a better quality A3. Swings and roundabouts.

The shift to common-rail diesel engines appears to have come off very nicely for Audi and its A3. The two 2.0-litre TDI common-rail units on offer are amongst the highlights of the range with their economy and performance characteristics. The lag and lunge of the older Audi diesels is gone and the power is piled on quietly and smoothly for a far more relaxing drive.

The A3 remains a thoroughly competent premium hatch and while some will yearn for a sportier edge to the driving experience, they'll find the build quality, design and engineering tough to fault. Audi has really been going places over recent years and with products like the 2.0-litre TDI A3s on the books, it's easy to get a handle on why.

TOP 5 A3 DEALS

The results below show the top A3 deals on buyacar

	Audi A3 2.0 TDi Sport 2dr Cabriolet Convertible
	ETR	Mthly £405	Saving £1,585	Price £22,500
	Audi A3 2.0 TDI 170 Sport 5dr Hatchback
	ETR	Mthly £340	Saving £1,999	Price £19,486
	Audi A3 2.0 TDI Sport 5dr Hatchback
	ETR	Mthly £324	Saving £1,899	Price £18,676
	Audi A3 2.0 TDi 2dr Cabriolet Convertible
	ETR	Mthly £372	Saving £1,440	Price £20,835
	Audi A3 2.0 TDI SE 5dr S Tronic Hatchback
	ETR	Mthly £326	Saving £1,926	Price £18,894

typical 11.64% APR

PCP finance quote over 48 months,  10,000 miles pa,  deposit of £1000