Audi A5 1.8 TFSI

It’s always a nice surprise when the cheapest engine turns out to be one of the best. This 1.8-litre turbo is smooth, punchy and surprisingly green. The fact that this model costs £2,285 less than a comparable diesel A5 is another bonus. Most drivers won’t opt for this base engine due to the lower running costs associated with diesels – and that’s a shame.

The big sellers in the facelifted Audi A5 range will definitely be the diesels, but the entry-level 1.8-litre TFSI petrol car looks like great value, too.

Even though it’s the cheapest model in the line-up, this four-cylinder turbo produces 168bhp – and this is all the power you’ll ever need out on the road.

That’s because peak torque arrives at anywhere between 1,400rpm and 3,700rpm, ensuring a surge of acceleration every time you press the throttle pedal. It’s enough for a 0-62mph time of 7.9 seconds – virtually identical to that of the higher-powered 2.0-litre TDI engine.

Step out of a diesel and into this car, and you’ll be amazed at how refined it is. At idle you can barely hear – or feel – the engine running, and it revs so quietly that pulling away smoothly requires a bit of practice as you have to base the amount of revs used on what you see on the rev counter, rather than the noise.

Wind and road noise are barely noticeable, too, which only adds to the impressive refinement. The only letdown is the ride, but this is something we’ve come to expect of S line cars like the one tested here. They’re perfect for twisty B-roads as there’s virtually no body roll, but rutted city streets reveal how firm the suspension really is.

Depending on where you spend most time driving, it could be worth buying a model without this set-up. Whichever you go for, the downsides of owning a petrol car over a diesel will always be the running costs, but this 1.8-litre turbo doesn’t fare too badly.

Official fuel economy stands at 49.6mpg, while CO2 emissions are 134g/km. A comparable diesel claims 61.4mpg and 120g/km respectively. Take into account the £2,285 price difference between these two engines, and the argument for the petrol car becomes stronger still.

For low-mileage motorists it’s a no-brainer; go for the petrol A5. For high-mileage drivers, get out the calculator and compare the long-term running costs, as it would be a shame to miss out on this great-value engine.