You simply can’t get a six-cylinder diesel engine in most cars of this kind. Jaguar doesn’t offer one. Alfa Romeo doesn’t either. Volvo is all about the four-pots these days and Lexus hasn't offered diesel engines for years. Mercedes-Benz offered a six-pot in the previous C-Class but not anymore. Audi does – in both the A4 50 TDI and the new S4, in fact. Even so, you could say the opportunity for BMW to boss the fast diesel executive market is now as clear as ever it was, and the 330d starts doing that with a combination of refinement, torque, smoothness and willingness to rev that still marks it out as a true great.
There’s remarkable strength of performance on offer from as little as 1500rpm right the way around the tacho until 4500rpm. Initial 'tip-in' throttle response can feel a little bit sudden and slightly over-keen when you’re looking to simply creep forwards in traffic, but it’s not problematically so. And whether you’re adding extra throttle midway through a gear or feeding it back in after a deceleration phase, the engine is ever responsive. Better still, it doesn’t seem to protest nearly as hard as a four-cylinder diesel when asked to really work, remaining smooth and relatively quiet at high revs and under lots of load.
The ZF eight-speed automatic gearbox seems almost as well-matched to the 3.0-litre engine as it does to the smaller 2.0-litre diesel, although it’s occasionally a little bit slow to kick down in the 330d's standard driving modes. If there’s a payoff for that, it may well be the real-world fuel economy, which really is great for a car of this size and performance level. Without being driven with much regard at all for economy, our test car returned an indicated 47mpg on a mixed motorway and A-road run of decent distance.
The combination of 19in wheels and adaptively damped M Sport suspension on our test car didn’t quite produce the most rounded or convincing ride-and-handling compromise we’ve experienced in a G20 3 Series, although it didn’t fall short by much. Having swapped passive dampers for adaptive ones and run-flat tyres for more conventional performance rubber, you expect this car to really hit the heights dynamically. But while the 330d offers slightly greater primary ride compliance and a more settled low-speed ride than other variants we’ve tested, it’s little if any quieter-riding on coarser surfaces and not immune to a very gentle but nonetheless perceptible spikiness in its close body control on more undulating roads.
That said, you’d be hard pressed to find anything other than the perfectly equipped 3 Series to ride or handle better. The M Sport torque-vectoring rear differential deals efficiently with the generous and accessible mid-range oomph of the 330d’s engine, making for handling that’s engaging and finely adjustable under power if you so choose – but also precise, composed and very effectively reigned-in at speed. About as absorbing and complete as in any sporting executive saloon on the planet, in other words.