Playing the manager's role, leading to locations and carrying vast amount of kit, the Audi has covered a fairly hefty 30,000 miles over the past year. But that's one of the main reasons we chose it - as evo's staff photographer I clock up a huge annual mileage. And with most of the miles being done on motorways and A-roads, it has been very agreeable to while away the hours in the supportive grip of the A4's leather seats, listening to the crisp sounds coming from the Bose sound system. And no, the expensive hi-fi isn't there to disguise the noisy diesel clatter - once you're up and running, most people would never even guess it's a diesel.

In fact once you get past the rattly start-up, the A4's 2.5-litre V6 sounds quite attractively throaty compared with most diesels. Its biggest flaw - and it's a surprising one - is that it isn't actually particularly economical.

Now I know the words 'diesel' and 'economy' usually go hand in hand, but in our hands the 2.5 rarely bettered 35mpg and the average fell below 33mpg. Okay, not bad considering the performance and the weight of the car, but not really a good enough reason to buy a TDi, especially since diesel in the UK tends to cost more than regular unleaded. One major plus, however, is that in 30,000 miles the A4 only had to have one service.

Having driven the 2.5's little brother, the 1.9 TDi, we'd have to say that the smaller engined car loses little in performance while giving better economy. The 1.9 also felt lighter on its feet - quite regularly on twisty back-roads the 2.5 would understeer heavily, while bumpy roads could have the suspension hitting the bump-stops. But we're talking extreme driving here. The orange ESP warning lights also became regular features on trips to Wales, occasionally joined by a strange red BRAKE WARNING light. Having checked, as the handbook suggested, the brake fluid reservoir, and having had the brakes looked at, the light still came on at random. As for the orange light, a heavy right foot seemed to be the culprit.

Quite early on we noticed the A4 was occasionally losing power under acceleration. This was finally attributed to a faulty connection on the fuel pump relay. These glitches apart, the build quality seemed to be well up to usual Audi standards. Even after 30,000 miles of hard use the interior was rattle-free, while the exterior (minus a couple of minor stone chips, a hazard of all those motorway miles) still looked as fresh as the day it arrived. So the A4 2.5 proved well-made, quick, comfy, classy and virtually painless to run.

Big boot, too, which comes in handy when you've a mountain of photographic gear to lug around. But it never completely sold itself to us. The economy wasn't special enough to put up with the diesel start-up rattle and limited rev-range, and it wasn't enough of a driver's car to tempt you off the motorway very often. Long journeys were its forte, just eating up the miles. I can't help thinking that sitting beside your 2.5 TDi in the garage you would have to have something smaller, more agile. Something more likely to appear in one of those evo group tests.