Audi A6 Avant 4.2 quattro SE

The previous-generation RS6 Avant quickly established itself as a cult model for fast car enthusiasts, but until a direct replacement arrives in 2007, fans of the brand will have to make do with this, the 4.2-litre V8 Avant quattro.

That's because this flagship model is currently the fastest big load-lugger Audi builds, boasting a slightly detuned version of the V8 powerplant fitted to the smaller S4 family.

The A6 Avant's smooth rear end looks typically classy, although the gently sloping roof clearly isn't designed for maximum carrying capacity. Even so, with the rear seats folded there's a decent 1,660 litres of load space.

While that's not enough to come close to the massive 1,910-litre cap-acity of the Mercedes E-Class Estate, it's a match for the BMW 5-Series Touring, which offers 1,650 litres. A pair of securing rails on either side of the boot prevent smaller loads moving about, while the car we drove also came fitted with an optional storage pack. This includes a retaining bar and strap for dividing up the space.

At the front the Avant sports the now familiar, distinctive Audi face, while under the bonnet lies a powerful engine boasting 330bhp and 420Nm of torque. It gives the big estate strong acceleration, with 0-60mph dispatched in only 6.2 seconds. Throttle response at speed is always good and every prod of the accelerator is accompanied by the unmistakably gruff sound of the V8.

Elsewhere, the successful Audi formula is evident, with the quattro four-wheel drive delivering superb grip, and a six-speed Tiptronic gearbox which offers auto or manual operation via steering wheel paddles. Our test car was also fitted with optional adaptive air-suspension. This features four settings - lift, comfort, automatic and dynamic - which can be selected through using Audi's MMI integrated cabin control system. However, at ΂£1,500, it's an expensive extra.

In the comfort setting, the ride is smooth and high-speed refinement excellent, making the A6 a relaxed motorway cruiser, while choosing dynamic noticeably stiffens the car's ride.

Inside, the cabin is superbly built, with leather upholstery, electrically adjustable seats and walnut trim as standard. However, while the big Audi is undeniably impressive, the 3.0 TDI A6 Avant has more torque, superior fuel economy, and at ΂£32,315, costs more than ΂£12,000 less than the V8.