There's more to a car than its engine, of course, but I found that I liked this A7 Sportback a lot more than the last one I drove. Audi sneaked in a mild update in between the two experiences, and that might have been thought to explain the discrepancy if only the changes had amounted to more than a facelift and a change of equipment.
However, they didn't, and I'm forced to conclude that the BiTDi engine has single-handedly put me in a better mood about a car I've had doubts about from the start. It's quite a piece of work. There's another 3-litre diesel in the range, but this one has two turbos rather than just one, and that doubling is responsible for a power hike to from 215bhp to 316bhp.
The 0-62mph sprint accordingly takes just 5.2 seconds if you're in the mood for that sort of thing. If you're not, the BiTDi will operate in a very relaxed manner, pottering around quite calmly but always prepared to gain speed rapidly if the need arises.
The aural effects are extraordinary. The exhaust system has been designed in such a way that the BiTDi sounds more like a burbling V8 than the V6 it really is, all the more so if you take advantage of a function in the drive select system to make it louder.
Do this and the roar during periods of hard acceleration is marvellous, and even in less urgent circumstances such as a motorway cruise the effect is similar to that of being followed at a respectful distance by a World War I biplane.
Drive select allows you to do a lot more than this. You can also use it to set various parameters (throttle response, gear selection characteristics, suspension damping and so on) either according to levels pre-determined by Audi or, if you choose "individual", by creating your own personal cocktail.
I did the latter, because I preferred the sportier set-up in most respects (particularly for the suspension, since it suits the 20-inch wheels and low-profile tyres better) but didn't think much of the eight-speed automatic gearbox's tendency to change down early and change up late. Too fussy. The more subdued setting, over-ridden manually if it necessary, seems more appropriate.
I enjoyed this A7 more than I thought I would, but the earlier doubts remain. Rear visibility is treacherous, for one thing. For another, Audi still needs to put the footrest in a more sensible place, an inch or two further from the bulkhead than it is now. It is plainly and simply ridiculous that a piece of equipment devised for the driver's convenience should be positioned in such a way that using it requires more effort than not using it.
People who might consider buying the top-level A7 probably don't worry too much about the cost, but it came as rather a shock to discover that the test car's optional extras boosted its price from just under £57,000 to nearly £71,000. It really doesn't feel worth that much, and while I understand that the Bose surround system is worth £1,000 of anyone's money I don't see the point of the £1,100 Sports differential, since this is not car you would buy with the intention of giving it large on corners.
£2,400 seems an extravagant price for non-standard interior inlays, and while £135 isn't much money in this context it strikes me as being a hell of a lot for a rear window blind that you have to operate by hand.
Still, the luggage compartment (535 litres with the rear seats up, 1390 litres when they're folded down) is impressively roomy, and justifies the Sportback part of the car's title. And although it's not visually distinctive, and would be difficult to spot in a line of large Audis, I thought it was quite telling that at one point I looked out of a window - from some distance and at an unusual angle, in my defence - and mistook the A7 for a friend's Jaguar XF. Perhaps it's a more elegant car than I've previously given it credit for.