Road Test: Porsche Panamera 3.0 [300] V6 Diesel 4dr Tiptronic S

This is, by a comfortable margin, the best diesel engine in the world. It's quieter and smoother than several petrols, and it's more powerful and refined than the really rather good engine it replaces.

It's roughly the same 3.0-litre V6 in the old Panamera diesel, but power has been upgraded to 296bhp, with torque up 74lb ft to 479 lb ft. That whips the 0-62mph time down from 6.8secs to 6.0, and improves top speed by 11mph to 161.

On the minus side, fuel economy has decreased fractionally from 44.8mpg to 44.1mpg, and emissions are up from 166g/km CO2 to 169g/km. And it's got a bit more expensive - base price has risen by £2,367 to £65,289.

But what you get - as well as that, er, divisive styling - is an utterly unique driving experience. Bolted to the seamless 8spd auto, it's always in the torque band, so acceleration from slip road to cruising speed is one continuous puff.

This thing weighs 1,900kg but it puts on speed like a lightweight saloon. OK, so it's expensive. And yes, the Aston Rapide is more beautiful and the Maserati QP is more soulful, but for untrammelled diesel perfection, and a genuinely different driving experience, this is your new car.