Audi reinvents its S5 as a replacement for the old S4. Jonathan Crouch takes a look.

Background

The Audi S5 was originally quite a different car, a sporty version of the Ingolstadt brand's mid-sized Coupe and Cabriolet designs, with a model lineage dating back to 2007. Today's S5 though, is rather different, either a five-door 'Saloon' or an Avant estate. In essence, it's a sportier version of the new-era A5, which in mid-2024 replaced the previous long-running A4 saloon and estate models, in line with Audi's change of combustion naming convention. That makes this modern-era S5 actually more of a direct replacement for the old S4 - which has a much longer model lineage, the very first S4 dating back in 1997. As this new S5 is today, the S4 was always a V6 (even when it was briefly sold as diesel in 2019), apart from a brief spell of V8 power between 2003 and 2009. That V8 was replaced by a supercharged V6 petrol S4 model, but in more recent times, the S4 used the kind of V6 turbo petrol powerplant that continues here with this modern era S5, launched in mid-2024. Let's take a closer look.

Driving Experience

As with the old S4, don't think of this S5 as any kind of super saloon or estate; its role is merely to be a very fast kind of A5, in keeping with the remit of its two most obvious rivals, the BMW M340i xDrive and the Mercedes C 43 4MATIC. The power output - 367PS from the 3.0-litre turbo petrol V6 - is much the same as it was from the previous S4 and usefully above the supercharged and V8-powered S4 models Audi sold in this sector a decade or so back. With 550Nm of torque on tap, rest to 62mph is dispatched in only 4.5s en route to an artificially-limited top speed of 155mph. Audi wants you to know that this modern-era S5 has more of an environmental conscience than its predecessors, apparently evidenced by the fitment of the brand's new 'MHEV plus' mild hybrid system, which is different from the old MHEV set-up in that in addition to the usual system-integrated starter-generator, there's also a second centrally-mounted powertrain generator. The result is dramatically increased levels of regenerative braking - and consequently, a bit more of a positive impact on efficiency. The frugality benefits though, are still relatively marginal. But Audi says it's worked to make this car more driver-focused, with stiffer suspension mounts, a more rigid front axle and more connected, progressive steering. Plus, there's a wider 'Audi Drive Select' mode spread between 'Comfort' and 'Sport'. There's quattro 4WD of course and the S5 also gets an electronic differential and torque vectoring. Under the skin, as with the ordinary A5, there's a new 'PPC' ('Premium Platform Combustion') architecture; almost revolutionary in an era where many other volume brands stopped developing combustion platforms some time ago.

Design and Build

In both five-door 'Saloon' hatch and Avant forms, you'd know this new S5 as an Audi, but a rather more modern one. There are the usual S-model touches - like big silver-framed front corner cut-outs, a subtle rear spoiler, unique wheels and a bespoke rear bumper incorporating two pairs of potent-looking tailpipes. As with the standard A5, slim LED headlights with customisable OLED technology flank the familiar Audi Single Frame grille. The long bonnet flows into a steeply raked windscreen with A-pillars shifted back by designer Jacob Hirzel to well behind the front wheels. The roofline dips away past the B-pillar and there's more fancy optional OLED lighting tech at the back, where the rear clusters can be made up of 364 segments offering a total of eight configurable lighting signatures. Key to the profile perspective are flared arches the designers refer to as 'Quattro muscle'. Inside of course, it's the usual modern screen fest, with unique S5 sports seats and a higher-set curved free-standing MMI infotainment display comprised of an 11.9-inch virtual cockpit instrument cluster and a 14.5-inch central touchscreen. There's a head-up display and a smaller 10.9-inch screen for the passenger side, which has a clever polarised filter so the driver can't be distracted by what's on it. This extra monitor could be used by the passenger to, say, set the sat nav or watch movies. There's certainly quite a feeling of luxury, embellished by a 'Softwrap' fabric panel that flows across the dashboard into the doors, both back-lit with subtle ambient lighting. The doors also get 'Smart Door Panel' controls which gives access to things like seat and mirror settings. And sustainable and vegan materials feature throughout. It'll feel roomier in the back than the old S4, thanks to 80mm of extra wheelbase length. Which now means that a couple of six-foot adults can sit on the more heavily bolstered rear seats more comfortably. Aided by a lower hip point for the seat base and a slightly raised position over the front seats that offers a better view forward. Out back, the hatch model's 445-litre boot capacity is down on the 480-litres of a rival BMW M340i saloon, but the space is easier to get at and rises to 476-litres in the S5 Avant.

Market and Model

Let's get to S5 pricing, pitched at the time of this Review in Summer 2026 at around £66,000 for the five-door 'Saloon' and from around £68,000 for the Avant estate - that's in base 'Black Edition' form. There's also a plusher 'Vorsprung' trim level. As you'd hope for these sums, equipment levels are generous. Top variants feature sport seats upholstered in diamond-stitched Pearl Nappa leather and include additional integrated front seat headrest speakers that form part of the audio upgrade to a Bang & Olufsen 3D premium sound system. The front seats also offer a ventilation and massage function, while the front and outer rear seats and the steering wheel are heated. The steering wheel is also electrically adjustable; there's a 10.9-inch MMI front passenger screen; and drivers can control vehicle and infotainment functions via a standard-fit configurable head-up display. Plus of course you get usual A5 features like navigation, a powered tailgate and a wireless smartphone charger, along with all the usual camera driver assistance safety systems. Those wanting to spend more will be tempted with digital OLED lights and adaptive damping. Another desirable option is the panoramic roof with Polymer Dispersed Liquid Crystals, which can transform itself from translucent to opaque at the touch of a button.

Cost of Ownership

The key engineering efficiency development with this new S5 is, as we told you in our 'Driving' section, its new 'MHEV plus' mild hybrid system. This is based on a 48-volt on-board electrical system that supports the combustion engine and reduces CO2 emissions while increasing performance. Its added powertrain generator (the 'PTG') enables electric driving components that contribute to a reduction in fuel consumption. The WLTP figures are 36.2mpg on the combined cycle and up to 176g/km of CO2. The 'MHEV plus' system offers advantages in CO2 emissions compared to the previous MHEV set-up. Over the WLTP driving cycle, these total up to 17g/km of CO2 from the S5's V6 3.0 TFSI petrol unit. The PTG can also add up to 24PS of electric power to the output of the combustion engine. When decelerating, the PTG feeds energy back into the battery at up to 25kW. As a result, purely electric manoeuvring and parking are possible to a limited extent. Thanks to the option of using an electric air conditioning compressor, the air conditioning system can also be operated when the vehicle is stopped at traffic lights and the combustion engine is switched off. With the integrated and blending-capable brake control system, the brake pedal and the brake hydraulics can be completely decoupled. Via the 'MHEV plus' system, it achieves the necessary deceleration without using the friction brakes thanks to regenerative braking. This means that deceleration is initially achieved solely by recuperation. The friction brakes only kick in when the brake pedal is pressed harder. The brake feel remains unaffected by this.

Summary

Quite a lot has changed in creating this new kind of S5. And quite a lot hasn't. It's a much classier overall package, both inside and out. And the gutsy turbo engine should make it feel properly quick - like the old S4 V8 models used to be. But the underlying demeanour on offer here is very little different. An S5 is a devastatingly quick tarmac cross country tool, its quattro 4WD system giving this model wet weather traction that most rivals still can't match. As ever though, if you want a sporting model of this sort to be some sort of dynamic hooligan, some sort of junior M3, you'd probably do better looking elsewhere. A typical S5 owner is really above all that sort of thing. He - or she - doesn't want the thrill-a-minute nervousness of an M3 or a C63 and isn't looking for a car that will replicate that with slightly less power for slightly less money. So Audi has delivered to that brief. Unless you do something stupid, this car won't introduce you to any sort of fear factor. Instead, it offers speed you can control confidently and extra traction that's telling in the kind of conditions that so often characterise this country. Would you take it on a track day? Almost certainly not. Would you enjoy a high speed trip through the Alps in one? Absolutely yes. None of this of course, endears the S5 to the tyre-smoking folk who write for car magazines. If you talk to someone about to write a cheque for a car of this kind though, so many of them will be more inclined to opt for the Audi.