The engine in the Alpina D3 is actually the powerplant from the 204bhp 123d, in this case breathed on to deliver a few more horsepower. It's a cracking engine and the two turbos mean that it pulls strongly and cleanly from low revs without the lag and lunge you often get with high power four-cylinder diesel units. Its 450Nm of torque is what makes the D3 such a beguiling drive, offering considerably more mid-range heft than a Porsche 911 GT3 RS.
This means a 6.6 second sprint through 60mph from standstill and a top speed of 152mph should you choose the saloon or coupe models. The heavier touring estate is fractionally slower but not by much. Ride quality seems better even on the big 19-inch alloys than a BMW 330d on 18-inch rims, probably due in large part to the fact that Alpina eschews run-flat tyres with their stiff sidewalls. There's plenty of feedback at the front wheels and the Michelin Pilot Sport 2 tyres and the Alpina's excellent body control encourages an exuberant driving style. The brakes are beefier too with better fade resistance than the standard BMW items.
The 19-inch alloy wheels will be the first thing most notice about the car but the subtle body kit also differentiates the Alpina D3 from workaday 3 Series models. The Alpina decal set is a no-cost option that is available in silver or gold. I'd find that hard to resist. The D3 is offered with metallic paint finishes only, which is another thing to consider when comparing prices with standard BMW diesels.
Otherwise the interior isn't that different to that of a normal 3 Series saloon, coupe or Touring but the Alpina roundels set into the part leather seats is a classy touch as is the Alpina dial pack. Build quality is very good, though the facia architecture is now starting to look a little dated, this E90 generation 3 Series having been with us since 2005 now. The D3's stance on its 19-inch alloy wheels looks agreeably aggressive and the front spoiler gives it genuine rear view mirror presence.
The Alpina D3 is offered in two specific guises - standard and Lux pack - the latter adding £3,100 to the price. Nevertheless I'd say it's the one to go for, largely because of the slightly odd way these cars are ordered by Sytner BMW in the UK. As the cars are built by BMW and enjoy the quality benefits that brings, Alpina GB receives a discount if the cars are provided to a 'set' specification, without the requirement for time-consuming one-off customisation. This means that Alpina will charge you a £1,550 bespoke order charge if you want to deviate from the standard specification. The Lux pack adds satellite navigation, voice control, Bluetooth, climate control and black high gloss trim. Add any of those items to the standard D3 and you pay for the item and the punitive bespoke charge.
This makes a D3 saloon with Lux pack £34,750, which compares with £35,960 for a 325d M Sport specified as closely as possible to the D3's trim. That buys a car with less power, a worse ride, smaller alloy wheels and none of the Alpina's exclusive look and feel.
As well as being effortlessly rapid, the Alpina D3 is also ruthlessly efficient, managing an incredible 52.3mpg combined fuel economy figure. Go for the six-speed automatic rather than the manual gearbox and that figure drops to 47.1mpg. The manual car will also emit a mere 144g/km of carbon dioxide. To further sweeten the deal, residual values of Alpina models comfortably outstrip those of standard BMW models.
BMW's 3 Series diesel is a hard act to improve. It's a fantastic product that's been rewarded with stratospheric sales success. Drive the Alpina D3, however, and you can't help but feel that not only has Alpina achieved exactly that but it has also done so at a price that's all but impossible to ignore. Trouble is, many UK buyers will.
Perhaps the fact that there's really only one Alpina dealer in the UK puts people off. Yes, Sytner BMW has a number of branches around the country but many people will still see the D3 as a specialist thing that's requires more care to run. The rewards are well worthwhile though. You get a car that rides more comfortably, looks better, feels special and offers greater exclusivity than a regular 3 Series. On top of that, the tweaked engine offers performance that's stronger than a 325d yet is far more economical and also costs less when equipment is taken into account. That sounds like a winning combination to me.