Last week Vauxhall announced details of its powerful range-topping Insignia VXR; this week there's a new model that resides at the other end of the spectrum.
The Insignia Ecoflex is based on the standard 2.0 CDTi 160 model and uses the same 158bhp 2.0-litre diesel engine, but it has a number of tweaks to improve fuel economy and cut CO2 emissions.
A 1cm lower ride height and aerodyamic under-body panels help the Ecoflex to cut through the air more efficiently, while low-rolling-resistance tyres also reduce friction.
Tweaks to the car's gearing help to cut down on the amount of fuel used, while a gearshift indicator advises the most efficient time to change gear.
Average fuel economy of 54.7mpg is 10% better than the standard car's, while the tweaks cut CO2 emissions from 154 to 136g/km - dropping the Ecoflex down from the 21% to 18% company car tax bracket.
Although emissions aren't as low as a VW Passat Bluemotion 2 or Toyota Avensis 2.0 D-4D 130, the Insignia Ecoflex betters the Ford Mondeo Econetic and has more power than any of these models.
Ecoflex versions of every trim Insignia variant (apart from SRi and VXR) are on sale now for a 475 premium over the model they're based on.
Prices start at 19,600 for the Exclusiv and rise to 25,745 for the Elite Nav model.