BMW 320d ED

What is it?

The business class 320d. The version we road tested in February is all well and good for the punters, but even as we lavished it with stars, BMW had this, the EfficientDynamics model, gently warming up in the trouser press for its corporate debut.

Despite looking for all the world like a regular 320d (there is no badging to distinguish the car from its stablemate) the ED is in fact a wheeled loophole intended to help its buyers circumvent as much of the government’s company car tax rules as possible.

It does this by playing the now-familiar technical trump card; output from the 2.0-litre diesel engine is reduced to 161bhp from 181bhp, the six-speed manual gearbox’s ratios have been lengthened, internal friction has been further reduced, ancillary power consumption has been revised and, most importantly, smaller 16-inch aerodynamic alloys have been fitter under the arches.

The result is a drop in CO2 emissions from an already impressive 120g/km to a positively tree-hugging 109g/km. Not only does this drop the ED into a lowly 15 per cent tax band under the latest rules, it also ensures that businesses which purchase outright will be able to write off 100 per cent of the cost against tax in the first year.

What’s it like?

Much as you’d expect; a BMW 320d with some of the starch taken out. Fortunately, there was such an excess of starch to begin with that there really isn’t much of a penalty to pay for the ED’s fiscal finesse.

The 20bhp reduction in power means that even in its Sport mode (BMW’s selectable Drive Performance Control comes as standard) there’s a marginal decline in top-end urgency, which translates into a half-a-second deficiency in the 0-62mph sprint.

Nevertheless, that still means that the ED is capable of breaking the tape in an athletic 8.0 seconds, and with the same 280lb ft of torque available from 1750rpm as before, the car very rarely (if ever) feels like a feeble low-emission special.

Indeed, it’s a measure of the model’s class-leading chassis credentials that nudging it into Sport remains a compelling option - one arguably bolstered by the new wheels, which with a more generous profile and no run-flat rubber, offer a further layer of polish to the 3-series’ already exemplary ride quality.

The same gently heightened sense of comfort is noticeable in the car’s default Eco Pro setting, where a remapped throttle and gearshift indicator help stretch the 320d’s claimed fuel economy from 61.4mpg to a best-in-segment 68.9mpg. (To put that in perspective, the VW Passat Bluemotion manages the same return, but only from a 1.6-litre diesel engine with just 104bhp.)

Should I buy one?

Yes, definitely. With unerring accuracy, BMW constructed an ideal (as it stands at the moment among its peers, virtually perfect) machine for fleet managers and tax-shy execs. They’ve even brought it to market at the same price as the 320d SE, and added the eight-speed automatic option which its customer base apparently craved.

However, if your pride and joy is not subject to company car rules, you should pause before jumping on the bandwagon. Certainly the drop in CO2 emissions is going to benefit you too, but only to the tune of £10 a year, and our long-term experience with the standard engine has already proven it capable of 60-plus mpg without the need to deduct any of its potential energy.

If it were our money on the line, we’d pony up an extra tenner for added thrust, prettier wheels and the quiet satisfaction of experiencing one of the decade’s finest at its undiluted best. But that’s just us.

BMW 320d EfficientDynamics

Price: £28,080; 0-62mph: 8.0 seconds; Top speed: 143mph; Economy: 68.9mpg; Co2: 109g/km; Kerbweight: 1490kg; Engine type, cc: 1995cc turbo diesel, four-cylinder; Power: 161bhp; Torque: 280lb ft; Gearbox: Six-speed manual

Read the What Car? verdict: BMW 320d EfficientDynamics