Engine, 0-60mph and gearbox
A wide range of petrol and diesel engines are available, starting with a 1.5-litre, turbocharged petrol that comes with either 138bhp or 163bhp. We’ve tried the higher-powered option and found it fairly fuel-efficient and flexible from low in the rev range. Given its small price, emissions and fuel economy penalty over the 138bhp version, we’d say the 163bhp version is well worth considering.
Alternatively, there's a 197bhp, 1.6-litre, turbocharged engine or a 256bhp 2.0-litre turbo – the latter of which comes exclusively with an eight-speed automatic gearbox and four-wheel drive. Both are quick but are also pricey to buy and comparatively expensive to run, so we’d stick with the less powerful 1.5-litre engines. .
Moving on to the diesels, there are four available: a 1.6-litre with 108bhp or 134bhp, and a 2.0-litre with 168bhp or 207bhp. The 134bhp 1.6 is the sweet spot of the range – gruntier than the 108bhp variant and not much slower than the far more expensive 168bhp 2.0-litre. The 207bhp 2.0-litre, meanwhile, isn’t particularly economical and is only available in with decidedly expensive GSI Nav and Elite Nav trim levels.
Suspension and ride comfort
When equipped with the standard suspension and relatively small 17in wheels, we found the Insignia Gran Sport handles smooth roads with crests and compressions in a relaxed – if slightly floaty – way. However, throw in some craggy surfaces and the ride quickly deteriorates, with the car fidgeting noticeably and thumping over sudden obstacles such as potholes.
Adaptive dampers are standard on the GSI Nav models and optional elsewhere in the range. Set in the softest Comfort mode, they offer greater pliancy over larger undulations, but the ride is still jittery over smaller imperfections, especially if you go for the biggest 20in wheels. In the stiffer Sport mode, the ride is just plain firm on UK roads.
Whichever suspension choice you make, try to stick to 17in or 18in wheels if ride comfort is important.
Despite having shed quite a lot of weight compared to the previous-generation car, the Insignia Grand Sport still feels relatively heavy in bends. The steering is reasonably accurate but, as you turn in to a corner, there’s a moment’s hesitation as the body leans over and only when it has settled does the car show eagerness to change direction. There is plenty of grip and balance, though, so you can carry speed with confidence.
The adaptive dampers sharpen things in their stiffer modes, allowing the car to change direction more keenly. This is even more the case with the sporty GSI Nav trim, which has lowered suspension with bespoke adaptive dampers that work together to keep body lean very well checked through corners. Its upgraded Brembo brakes are also meaty and reassuring, adding to your confidence.
Noise and vibration
Although they can be identified as diesels from outside, the 1.6 and 2.0 engines are impressively hushed from behind the wheel. At idle and under acceleration, you’ll hear some clatter and feel a few vibrations through the controls, but things are generally peaceful. Slot the relatively slick six-speed gearbox into top gear on the motorway and you’ll barely hear the engines at all.
So that’s the good news. Now for the bad: even with the smallest 17in wheels, road roar is surprisingly noticeable at all times. It builds up to become a constant and irritating drone at motorway speeds and, particularly on coarse surfaces, this makes it hard to relax. It gets worse if you add bigger wheels, to the point that the background noise on 20in wheels is quite unacceptable in a car designed for motorway jaunts.