So, assuming you’re willing to take an educated gamble, which way should you jump? It wasn’t very long ago that the decision would have been made for you. BMW had the fast diesel niche largely sewn up for a decade or more. That was until three years ago, when Audi started ushering its 3.0-litre, 300bhp-plus BiTDI V6 diesel into its A6, A7 and Q5, giving people an alternative to BMW’s 35d models for the first time.
Renowned BMW tuner Alpina subsequently leaped to the defence of Munich’s honour, fitting an overhauled 345bhp twin-turbo 3.0-litre straight six into its D5 Biturbo in 2012, and then into the current F30-generation 3 Series-based D3 Biturbo in 2013. The D3 Biturbo was cracked up as the fastest diesel production car in the world and, along with the rest of the 3 Series, has just been facelifted.
So as well as the many mechanical tweaks to the standard 3 Series’ steering and suspension made for BMW’s facelift this year, the Alpina D3 Biturbo inherits BMW’s improved interior, on top of which Alpina adds its own inimitable layer of material lavishness, notably via beautifully tactile lavalina leathers and downy Alcantara.
The D3’s is now a cabin entirely becoming of a £50,000 car, whose new satin chrome highlights set it off a treat. Alpina’s usual hallmarks – white-on-blue instruments, Alcantara steering wheel with blue and green stitching, those Alpina crests on the steering wheel boss and seats – lift the 3 Series’ ambience to new heights of richness and charisma.
But the A7’s interior is equally rich in its own way, and even more solidly constructed, although its style is much more restrained. Our test car’s mix of black, silver and grey trims make for a much more sombre feel than the D3’s. But although some of the Audi’s fittings are showing their age, its technical highlights – intelligent LED headlights and a large multifunction colour trip computer capable of relaying navigation mapping in crisp detail, to name just a couple – still really distinguish the car.
The Audi’s front seats are larger and more comfortable than the Alpina’s, its second row better endowed with leg room and its boot more generous on overall capacity in normal five-seat mode, below the window line.
The Audi is the bigger car, of course, so such things should be expected. Sure, the Alpina’s cabin is the warmer and more inviting, but it’s the Audi that’s the more luxurious, and comfort matters in an everyday-use high-mileage motorway machine.
But outside-lane punch matters, too. And although the Audi’s superior size wins it points on long-range comfort, it also threatens to prevent it from scoring as a driver’s car.