Car group tests

Audi S3 Saloon vs Mercedes CLA 45 AMG

Audi's sizzling S3 saloon takes the fight to Mercedes' CLA 45 AMG in the battle of the fast four-doors

Fast four-door saloons have been a staple of Audi’s model line-up for decades, but this is the first time the A3 has been given the trademark go-faster treatment.

By packaging a muscular 296bhp turbocharged engine and quattro all-wheel-drive system into the handsome A3 Saloon body, Audi has created the S3 Saloon – a car that aims to blend scorching performance and agile handling with sharp-suited style and plenty of premium kerb appeal. Andat around £33,000, it looks like decent value, too.

However, Audi isn’t the only German brand that offers a hot version of its smallest saloon, because Mercedes has treated its sleek CLA to a muscular makeover courtesy of in-house tuning division AMG.

Featuring a turbocharged 2.0-litre engine that boasts a dizzying 355bhp, as well as the company’s grippy 4MATIC all-wheel-drive transmission, the CLA 45 has all the right ingredients to take the fight to its S3 Saloon rival.

Audi S3 Saloon review

Mercedes CLA 45 AMG review

This exotic specification comes at a price, though, because the Mercedes will set you back by almost a hefty £42,000. So which of our heavy-hitting duo will land the knock-out punch in this encounter?

Click the links above to read each review, then read on for our verdict.



On paper, there’s little to separate the Audi S3 Saloon and Mercedes CLA 45 AMG for versatility. The Mercedes’ 470-litre luggage space is 80 litres larger than the Audi’s, but the S3 offers more head and legroom for rear passengers. 

The CLA is hampered by its high-backed front seats and narrow side windows, which create a claustrophobic feel for those  in the back. A sloping roofline and narrow door openings also make for tricky access to the rear bench.


Many buyers will put up with the compromised practicality to get such a bold design. While the subtle Audi looks every inch the traditional three-box saloon, the CLA apes sleek and stylish coupés. The blend of A-Class hatchback nose and rakish rear end is a little awkward, but it catches the eye. 


1st place: Audi S3 Saloon

The Audi S3 Saloon is fast, composed and agile, plus it has a classy cabin and decent practicality. Better still, it can switch from sports saloon to cosseting compact exec at the flick of a switch. Factor in the £10,000 saving over the Merc, and the Audi is a worthy winner.

2nd place: Mercedes CLA 45 AMG

When it comes to style and excitement, the rakish and raucous Mercedes CLA has the upper hand over the Audi S3. It’s also blisteringly quick and has incredibly sure-footed handling. Yet it’s not as comfortable as the Audi, while the hefty price tag and running costs are hard to ignore.


 Audi S3 SaloonMercedes CLA 45 AMG
On the road price/total as tested£33,245/£39,855£42,270/£54,715
Residual value (after 3yrs/36,000)£18,218/54.8%£21,854/51.7%
Annual tax liability std/higher rate£1,651/£3,301£2,186/£4,377
Annual fuel cost (12k/20k miles)£2,894/£4,824£3,058/£5,096
Ins. group/quote/road tax band/cost36/£407/G/£18045/£575/G/£180
Cost of 1st/2nd/3rd service£17pcm (3yrs)£24pcm/2yrs 24k
Engine4cyl in-line/1,984cc4cyl in-line/1,991cc
Peak power/revs296/5,500 bhp/rpm355/6,000 bhp/rpm
Peak torque/revs380/1,800 Nm/rpm450/2,250 Nm/rpm
  7-spd auto/rwd
Transmission6-spd man/4WD 
Fuel tank capacity/spare wheel55 litres/space saver56 litres/sealant
Boot capacity (seats up/down)390/845 litres470 litres/N/A
Turning circle/drag coefficient11.0 metres11.0 metres
Basic warranty (miles)/recovery3yrs (unlimited)/3yrs3yrs (unlimited)/4yrs
Service intervals/UK dealersVariable/121Variable/136
Driver Power manufacturer/dealer pos.12th/23rd*9th/12th*
Euro NCAP: Adult/child/ped./stars95/87/74/591/75/74/5
0-60/30-70mph5.6/4.8 secs4.5/3.9 secs
30-50mph in 3rd/4th/kickdown2.6/3.6 secs2.3/3.8 secs
50-70mph in 5th/6th/kickdown4.5/5.8 secs/N/A4.6/6.9/13.3 secs
Top speed/rpm at 70mph155mph/2,500rpm155mph/1,800rpm
Braking 70-0/60-0/30-0mph51.1/36.1/10.4m41.3/30.8/9.7m
Noise outside/idle/30/70mph26.2/5.8/317 miles24.8/5.5/305 miles
Auto Express econ (mpg/mpl)/range31.0/48.7/40.4mpg31.0/47.9/39.8mpg
Govt urban/extra-urban/combined6.8/10.7/8.9mpl6.8/10.5/8.7mpl
Govt urban/extra-urban/combined249/162g/km/25%263/165g/km/26%
Actual/claimed CO2/tax bracket  
Airbags/Isofix/cruise controlSeven/£345/£275Seven/yes/£300
Electric/leather/heated seats£1,305/yes/£225Yes/yes/yes
Met paint/xenons/split/fold rear seatsYes/yes/yesYes/£1,640^/£300
Park sensors front/rear/climate ctrl£525/yes/£425£660/yes/no
Sat-nav/DAB radio/Bluetooth£495/yes/yes/yes£495/yes/yes/yes

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