Road Test: Volkswagen Passat 1.9 BlueMotion TDI DPF 4dr

They've only gone and pimped up the Passat.

No, don't laugh. They really have. The BlueMotion version of the world's dullest car ticks all the bling boxes: lowered, bodykitted, tweaked engine, liberally chromed.

There's even a new in-car entertainment system: a dash display which, like a bossy elderly relative, spends more or less all the time telling you that you're revving too high. Ah.

Yes, the Passat is the latest car to get VW's BlueMotion treatment, a bunch of green mods aimed at reducing emissions and boosting economy. New spoilers and underbody skirt improve air flow, while the lowered ride reduces the drag coefficient by 12 per cent.

VW's engineers have tweaked their existing 1.9 turbodiesel, too: lowering the idle speed and fine-tuning the charge pressure, injection timing and exhaust gas recirculation rate. Simple, eh? They've also lengthened the gearing and given the Passat a nice new set of hard compound, high pressure tyres.

The results are impressive, with CO2 emissions cut from 148g/km to just 136g/km and combined economy up from 48.7mpg to 55.3. However, all these eco-mods translate to a less-than-stimulating performance.

Though acceleration remains as quick as the stock Passat diesel - and top speed has even been fractionally increased due to the longer gearing and slippier body - there's a definite laziness to all the BlueMotion's responses.

And it's noisy. While there's not quite the mechanical racket of the toolchest-in-a-washing-machine Polo BlueMotion, it doesn't have the timbre of a finely-fettled oil-sipper. The harder tyres grumble at motorway speeds, too.

So the Passat BlueMotion alone won't turn the world green, but it does at least demonstrate that you can eke out real fuel savings with but a raft of minor modifications. What if the world of maxed modifiers picked up on this whole green thing?

Imagine the legions of tracksuited bling-merchants fighting to create ever-more economical rides: old Novas with monstrous drag-lowering bodykits; idle speeds dropped like they're hot; car park meets swopped for wind tunnel sessions and assiduous study of fuel receipts. Mark my words: it could catch on.

VW Passat becomes pimping pioneer? Now that's what I call climate change.