What is it?
So slick are the cars that it’s easy to forget Alpina is barely out of nappies when it comes to sales volumes – especially when compared with BMW, the company with which Alpina has indelible historical ties and on whose products those slick cars are based.
Take the least expensive and often most popular model in the line-up, the 3 Series-based D3. Between 2013 and 2018, Alpina sold 460 D3 saloons and 790 estates in the old shape.
It’s an almost microscopic sum that makes those machines rarer than any mainstream supercar, but to Alpina, it represented a cornerstone of the firm’s revenue and meant a successor simply had to be built, even in the face of rapidly deflating demand for diesel power in Europe. And that’s what the ‘D’ in D3 stands for: diesel.
That successor has now arrived in the UK, the G20-generation-based D3 S, albeit tested here in G21 Touring guise. But for the badges on the bootlid, it is outwardly identical to the petrol-powered B3 (B for ‘benzin’) of five-star road test fame, with subtly draped skirts and bumpers, and the option of forged 20in multi-spoke wheels, which our test car has.
However, starting at around £55,000, the D3 S costs much less than its M division-engined, AMG-rivalling sibling and instead goes up against the recently dieselified Audi S4 Avant and… not much else, actually, unless you include the very entity whence it came.
Every D3 S starts life as an M340d xDrive, but then morphs considerably. First and foremost, BMW’s 3.0-litre mild-hybrid straight six receives an Alpina-specific cooling system, with two external radiators and an enlarged intercooler and fan.
The result is 350bhp and an elephantine 538lb ft – figures that are 15bhp and 22lb ft up on the M340d xDrive and also surpass those of the V6 Audi, although fuel efficiency drops from 44.8mpg in the BMW to 37.2mpg for the Alpina.
Elsewhere, the driveshafts have been reinforced and the chassis shares the same revisions as the scintillating B3: greater camber for the front wheels, bespoke spring and damper units, bigger brakes and Alpina’s own calibration for the torque split between axles, limited-slip differential and steering.