Mercedes C180 Coupe

While the Mercedes looks great and boasts an excellent ride and handling balance, it’s hobbled by an engine that lags behind the best – for both performance and efficiency. The C-Class isn’t as roomy inside as the Audi, either, while weaker residual values and higher CO2 emissions make it costlier for private buyers and company users alike.

You don’t have to sacrifice style to go green – just take a look at the latest addition to the Mercedes C-Class Coupe line-up for proof. The new C180 AMG Sport slots in at the bottom of the range, with an efficient petrol engine that promises the same performance as its predecessor, but with better economy and lower emissions.

On top of that, there’s a racy new Sport Plus trim level that adds even more appeal to the already desirable Coupe. There’s certainly no doubt that the Mercedes looks the part, and it easily trumps the / in the style stakes.

The two-door coupe roof and rear blend with the C-Class front end, while the Sport Plus model takes its cues from the muscular C63 AMG. Highlights include eye-catching two-tone 18-inch alloy wheels and a neat bodykit with a subtle tailgate spoiler.

It’s a similar story inside, where the usual classy C-Class cabin has been given a low-key makeover. The upright dashboard, logical layout and top-notch quality are carried over from the standard coupe, while the Sport Plus gets a visual boost from a pair of chunky AMG seats and some distinctive red stitching for the steering wheel, door panels and centre console. And while the cabin isn’t quite as stylish as the A5’s, the Mercedes matches its rival for standard kit, with climate control, Bluetooth and a DAB radio all included.

However, the C-Class falls a little short of the Audi when it comes to practicality and space. Occupants in the back get a similar amount of legroom, but the lower roofline means that taller passengers will have their head wedged against the roof. The problem is worse on models with the £1,350 optional panoramic roof, which lets in extra light, but at the expense of headroom.

The driver fares better thanks to plenty of seat and wheel adjustment, yet a high-set driving position means those over six feet tall will face the same problem as their back seat passengers.

Still, there’s plenty of useful cubby space scattered around the cabin, plus the square-shaped 450-litre boot is only five litres smaller than the Audi’s. And it’s not just the Mercedes’ boot that’s at a size disadvantage, because the C180’s new 1.6-litre engine is smaller and less powerful than the 1.8-litre TFSI in the A5.

As a result, the C-Class failed to keep up at the test track, where it needed 9.1 seconds to get from 0-60mph – over a second slower than the Audi. Our C-Class featured the £1,500 optional seven-speed automatic gearbox, but an example equipped with the clunky standard six-speed manual transmission wouldn’t be any faster.

At least the new engine is smooth, revving cleanly and crisply all the way to the red line. And while it doesn’t feel as potent as the A5’s engine, the turbocharged 1.6-litre’s relaxed and refined delivery is more suited to the C-Class’ grown-up character. Combined with the slick auto gearbox and supple ride, it makes the Mercedes an effortless motorway cruiser. Yet this relaxed nature doesn’t come at the expense of handling.

Standard-fit adaptive dampers, precise steering and a traditional rear-wheel-drive layout all help the C-Class to feel agile and engaging on a twisting back road. Although it doesn’t have as much grip as the Audi, the Mercedes’ major controls are better weighted and boast more feel.

At £32,590, the C180 AMG definitely isn’t cheap – although opting for the manual gearbox reduces the list price to £31,090, which is only £525 more than the slightly less well equipped Audi. The C-Class also suffers from weaker residual values and higher CO2 emissions than its rival, plus its 35.9mpg fuel economy figure was less than we managed with the faster A5.

The question is whether the C-Class Coupe’s superior style and relaxing driving experience are worth the extra money.