We thought that once there was a decent semi-automatic gearbox, it would turn the diesel engine into a great proposition for drivers wanting lots of fun.
So here we are, about to find out whether that assumption is true. Audi's new Direct Shift Gearbox (DSG) uses a twin multi-plate clutch and electro-hydraulic control to hold two gears at the same time: the one you are using and the one you are about to use.
The preselection means that changes are super-fast, at about 0.02 of a second, and it can be used in fully automatic or paddle shift mode. It will also blip the throttle automatically to smooth out shifts and there is little increase in fuel consumption or emissions.
The DSG gearbox is very clever and mightily impressive in cars like the TT 3.2 V6 but to an extent the performance and smoothness of the V6 engine tends to mask the gearbox's abilities.
It's only when you get it in a diesel car that it becomes obvious just what a fantastically well-sorted piece of kit it is.
For all their attributes like pulling power, economy and emissions, diesel engines do have some faults still. Unlike petrol engines, the power and torque bands are still very short and with a six-speed manual transmission you spend a lot of time pounding the gearlever from one slot to the next to get the most out of it.
Overtaking is often one time when drivers get caught out with diesels, as they suddenly run out of revs and have to hurry into the next gear.
Another fault of diesels is the difficulty in making smooth downshifts. I'm reliably informed by an engineer that it's the high compression ratio in the cylinders that makes it hard to make them seamless, unless you match the revs perfectly and it can take a lot of the fun out of driving diesel-engined cars.
Why am I pointing out all these various niggles? Because the DSG gearbox solves them all. It takes all the best elements of diesel-powered cars and then works around the imperfections.
Acceleration becomes a continuous stream of torque followed by power and upshifts take place in the proverbial blink of an eye.
Although the gearing is still short, it doesn't matter like it does with a manual because the gearbox has the next cog ready and it comes in without a break.
Downshifts are dealt with in the same perfunctory manner, thanks to a computer which blips the throttle to match the revs perfectly.
It begs the question: if there is no penalty for emissions or fuel consumption and you can find the extra £1,400 the DSG box costs, why would anyone choosing a diesel-engined A3 go for a manual over the auto?
It's not all a bed of roses though, because the 138bhp 2.0 TDI is still relatively noisy, but the speed this car accelerates at makes up for it.
The interior is beautifully put together, although there's not much space and in SE guise, this car has enough equipment to avoid the usual accusation levelled at Audi of stinginess.
Audi A3 2.0 TDI SE DSG
Delivered price, standard car (P11D value): £20,777
CO2 emissions (g/km): 157
BIK % of P11D in 2002: 17%
Graduated VED rate: £135
Insurance group: 11
Combined mpg: 48.7
CAP Monitor residual value: £9,050/44%
Depreciation 18.19 pence per mile x 60,000: £10,914
Maintenance (2.66 pence per mile x 60,000): £1,596
Fuel (7.71 pence per mile x 60,000): £4,626
Wholelife cost (28.56 pence per mile x 60,000): £17,136
Typical contract hire rate: £399 per month
##A3 DSG rear--none##
Three rivals to consider
The A3 tends to sit on its own a little at this price point: there are very few automatic premium cars around the £20,000 mark. As a result we've delved into the volume sector for the Golf and taken the bottom-of-the-range BMW and Mercedes-Benz.
For the price, the Golf is easily the best specified and the SE spec A3 is decently kitted out, with climate and cruise control and CD player. The other two are suitably sparse.
It's no real surprise that the Volkswagen comes out the best on servicing, maintenance and repair as it's not a premium brand, but it's only just cheaper than its Audi A3 cousin.
The BMW works out the most expensive, as this is not judged with a Service Inclusive package, which would cut costs appreciably. The Golf is a decent £1,596, while the 3-series Compact works out at £2,298.
Automatic gearboxes can be thirsty beasts, even in diesel-powered cars, and that's true of the BMW and Mercedes-Benz, which are affected by it. It means that they are considerably more expensive.
Over 60,000 miles, the 320td costs £6,036 and the Sport Coupe £5,766. The two DSG-mounted cars are much better, although the A3 is the best thanks to its weight advantage and three-door format. It would cost £438 less than the Golf in fuel.
Depreciation is the area in which the Golf excels. That's due to its attractiveness in the secondhand market keeping values high (at premium brand levels), while it has a lower front-end price to keep cash lost to a minimum. As a result it is miles ahead of the 3-series and Sport Coupe and just over 1ppm ahead of the A3.
In terms of cash lost over 60,000 miles, the Golf would lose £10,176, while the heaviest loser, the Sport Coupe, would lose £13,086.
By virtue of a convincing win in the depreciation comparison, the Golf wins on running costs. But if it didn't, that would be quite a shock considering its volume aspirations and fleet focus.
However, the Audi is close behind while the other two languish way back in premium price territory. It is tight at the top, but the question has to be asked: is a chopped-off BMW or cheap Merc worth paying £4,000 extra for over a Golf?
Emissions and BIK tax rates
It's a family affair when it comes to tax.
The A3 and the Golf have lower emissions and are Euro IV compliant, while the 320td and Sport Coupe emit more CO2 and are only Euro III. Tax for the Audi and Volkswagen is almost exactly the same at about the £1,400 (although the Golf is still the cheapest), while the Compact would cost a 40% tax-payer £2,244 – £200 more than the Merc.
BMW can't wait for the 1-series. The Compact is outclassed in nearly every way except driving involvement, while the Sport Coupe shows itself to be expensive in every way and isn't a particularly good drive.
The Golf and Audi are evenly matched, have great gearboxes and are excellent fleet propositions. But most people would be happy with a Golf and it's marginally cheaper as well.