Half a century in the making, Alpina’s big-seller appeals to both head and heart, says Alex Grant.

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SECTOR Compact Executive   PRICE £48,000-£50,000   FUEL 52.3-53.3mpg   CO2 139-142g/km

On paper, Alpina’s biggest-selling model sounds too good to be true; a 50+mpg executive saloon (or estate) that’s also one of the world’s fastest production diesel cars, delivering 62mph from rest in just over four and a half seconds. But this hand-finished bahnstormer isn’t only real, it’s got its sights set on business users.

The D3 Biturbo isn’t a typical 3 Series. Alpina is a manufacturer in its own right, with a 50-year heritage developing luxurious, high-performance cars through a unique, deep-rooted partnership with BMW. Deep enough that BMW not only approves and warranties the work, and supplies it with cars direct from the factory, but that Alpina has access to the newest models before they launch. Every car is individually numbered and registered as an Alpina, not a BMW.

That close partnership results in a thorough overhaul. The D3’s engine is based on BMW’s 3.0-litre six-cylinder diesel, but with twin turbochargers instead of the usual sequential setup, and gets optimised cooling and improved airflow all the way through to the performance exhaust system. This bumps power up to a muscular 345bhp, delivered through an eight-speed automatic transmission that’s been reprogrammed to make the most of the performance on offer.

Chassis upgrades are just as significant; adjustable dampers, larger brakes and a limited-slip differential help put the power down as effortlessly as possible through the 20-spoke wheels. Even the apparently cosmetic upgrades are functional, the front spoiler channelling air into the cooling pack behind the front bumper, and reducing lift at speed. Alpina also tunes the suspension geometry to match the size of wheels fitted to each car.

It takes a lot to improve on the 3 Series, but this is utter witchcraft. The D3 manages a multitude of talents; relentless in-gear acceleration with huge pulling power at low revs, yet delivered without the unnerving feeling that it’s struggling to hang onto the road. It feels sure-footed and agile when you want it to, yet also incredibly compliant (Sport mode aside) thanks to the adaptive suspension and non run-flat tyres. It’s more of a grand tourer than a sports car; so well set up, and so effortless at high speed, that you could cross entire continents without noticing.

An Alpina is an exclusive choice, but UK importer, BMW dealer Sytner Group, is used to selling these to business users and there’s a system in place to support it. You can buy and service a D3 at any Sytner site (or have it collected and delivered), there’s a dedicated corporate hub for lease customers and popular options have been bundled so they have a Cap Code to help with residuals. It’s a bespoke process, businesses can add extra lighting or signwriting if needed – including the no-cost retro pinstriping in silver or gold – and Alpina GB offers a one-to-one handover for customers.

Too good to be true? Not at all. The 3 Series has always been a brilliant way to keep your business moving – the D3 Biturbo takes the ‘Ultimate Driving Machine’ to the next level.

What we think

A supercar with a sensible side. Alpina might be an enthusiast brand, but the D3 Biturbo makes a brilliant business tool for those lucky enough to choose one.