The facelifted Vauxhall Insignia has been spied with minimal disguise, ahead of its planned reveal at the Frankfurt motor show in September.

It's expected to be revealed alongside updated versions of the Insignia saloon and hatchback. Myriad cosmetic changes have been carried out, all in an attempt to improve the Insignia's desirability. 

Previously pictured during cold weather testing in the Arctic circle, the 2013 Vauxhall Insignia estate will feature the same revised front end as the other bodystyles and a new diesel engine.

The spy shots revealed an undisguised grille, as well as updates and improvements to the interior. The Insignia also carries a more pronounced front splitter and fins which extend downwards from the front bumper in an attempt to smooth airflow.

Although LED daytime running lights will be fitted, the revised headlights fitted here do without integrated LEDs. Little is known about modifications to the rear end, but heavily disguised taillight units suggest changes will be made.

Mechanical changes will be slight, although there is the adoption of a new 1.6-litre turbodiesel to replace the aged 1.7-litre engine used elsewhere in the Vauxhall range.

The all-new powerplant is expected to offer a new CO2 champion in the range, undercutting the 119g/km produced by the greenest Insignia Sports Tourer.