Just like any other Insignia, the GSi is available in either Grand Sport or Sports Tourer guises, and the choice of a petrol or diesel engine increases the number of possible model variations to four.
The quickest? That’s the Grand Sport with the 256bhp 2.0-litre turbocharged petrol motor – the same car that bettered the old Insignia VXR’s Nürburgring lap time despite having 65bhp less power. Being 160kg lighter than the older car was likely a key factor.
The Insignia GSi Sports Tourer we opted to test, however, is powered by Vauxhall’s diesel engine. It’s the same 2.0-litre four-cylinder biturbo unit you’ll find in the Insignia Elite Nav and Country Tourer models – and so, a touch disappointingly, perhaps not what you’d consider a dedicated ‘performance’ engine – but it makes a pretty healthy 207bhp at 4000rpm and 354lb ft from 1500rpm.
This is sent to all four wheels via an eight-speed automatic transmission – the first to be fitted to a Vauxhall – while a GKN Twinster e-diff aids traction by managing the distribution of torque actively between the rear wheels.
Structurally, the GSi sits on the same E2 platform that underpins all Insignia models. Suspension comprises MacPherson struts and coil springs at the front, with a five-link axle and coil springs at the rear.
For the GSi, though, Vauxhall has dropped the Insignia’s ride height by 10mm and stiffened the spring rates by between 35% and 40% depending on the engine and bodystyle.
Flexride adaptive dampers are standard fit and offer a choice of three configurations: Standard, Sport and Tour. All variants ride on 20in alloy wheels that are shod in 245/35-sized Michelin Pilot Sport 4 S tyres.
Each of these wheels is 1.5kg lighter than the comparable 20in alloy offered on lesser Insignia models. Four-cylinder Brembo front brakes also provide improved stopping power.