New Vauxhall Insignia Grand Sport vs used BMW 4 Series Gran Coupe – driving

On standard suspension, you’ll find that neither of these cars delivers perfect ride quality. The Insignia’s is more relaxed and wafty, but it’s thrown off by smaller bumps which thump through to the occupants in a rather undignified way. The 4 Series’ is more controlled, but still rides stiffly over lumps and bumps in the road, preventing the car from ever settling down. You can specify adaptive dampers on the Insignia, while you can find 4 Series out there with such things fitted – which is worth doing if you can.

The pay-off for the 4 Series’ slightly lumpen ride is excellent handling. You get fast, direct steering that allows you to place it on the road perfectly, while the rear-driven chassis ensures there’s plenty of mobility and the car alters its line nicely in response to throttle inputs. By contrast, the front-driven Insignia feels rather wooden in corners, attempting to push its nose ahead all too readily, and lacking the same sort of sharpness to its steering. Still, it is at least grippy and well balanced.

The 4 Series takes the win again when it comes to performance. Both cars come with a 2.0-litre four-cylinder turbo diesel, but the Insignia’s only has 168bhp to the 4 Series’ 187. The result is that the BMW can get to 62mph from a standstill 0.7sec faster than the Insignia, and offers more mid-range punch too, making it more flexible.

New Vauxhall Insignia Grand Sport vs used BMW 4 Series Gran Coupe – costs

Our target price for the Insignia – in other words, the price you should aim to pay after haggling at a dealership – is £25,767. That suggests discounts on the Insignia aren’t that easy to come by, as that’s a relatively paltry £758 off the car’s list price. Turning to the used market, you’ll actually have to pay slightly less than that to get yourself a good, year-old 4 Series with average mileage – we found one example for sale for £24,975.

Of course, the difference between the two cars is that the Insignia comes with a whole extra year’s worth of warranty on it. But you can negate this downside to the 4 Series by specifying BMW’s extended warranty – the cost of which should, conveniently, be about the same or less than the price difference between the two cars.

Chances are you’ll find little to split these two cars in terms of the odds of something going wrong too. BMW and Vauxhall finished 17th and 18th respectively out of the 32 manufacturers in the 2017 What Car? Reliability Survey. We don’t have data on this generation of Insignia as it’s too new, but the previous generation came equal 15th out of 24 cars in the executive car class, while the 4 Series Gran Coupe finished 10th.

Where you will find a difference is in terms of fuel efficiency. This gets a little tricky to compare, because the 2017 4 Series’ figures were achieved under a newer, stricter testing standard than the 2018 Insignia’s. However, the 2018 4 Series, which is the same car under the skin, has been tested under the new regime, so it’s fairer to use its 57.6mpg average figure for the purposes of this comparison. Even then, the Insignia doesn’t fare too well, with an equivalent 51.4mpg.

Both cars should cost £140 a year to tax, assuming you buy yourself a 4 Series registered after 1 April 2017, when the tax system changed. However, keep in mind that if you buy a 4 Series with lots of options on it, those options might have tipped it over the £40,000 price threshold when new, meaning you could find yourself in the higher rate £450-a-year tax band instead. It might also be worth seeking out a 420d made before April 2017, in which case you’ll only pay £30 a year tax, as it will have been registered under the old system.