Audi RS5 Sportback vs Porsche 718 Cayman GT4 RS
Compare the Audi RS5 Sportback vs Porsche 718 Cayman GT4 RS. The Audi RS5 Sportback is £43,000 cheaper. The Porsche 718 Cayman GT4 RS is 0.5s quicker to 60mph. The Audi RS5 Sportback is more fuel efficient. Full performance, cost & ownership breakdown.
The Audi RS5 Sportback is priced from £65,000, powered by a 2.9L Twin-Turbo V6, producing 444 hp, with 600 Nm of torque, reaching 0-60 mph in 3.9s, a top speed of 174 mph, sent to the road via all-wheel drive. The Porsche 718 Cayman GT4 RS is priced from £115,000, powered by a 4.0L Flat-6, producing 493 hp, with 450 Nm of torque, reaching 0-60 mph in 3.4s, a top speed of 196 mph, sent to the road via rear-wheel drive.
The Audi RS5 Sportback offers a 480-litre boot, folding rear seats, runs on petrol, returns around 30 mpg, is covered by a 3yr / unlimited mi warranty. The Porsche 718 Cayman GT4 RS offers a 125-litre boot, a usable front boot, runs on petrol, returns around 23 mpg, is covered by a 4yr / 50k mi warranty.
On cost of ownership, the Audi RS5 Sportback is £43,000 cheaper than its rival, the Audi RS5 Sportback costs less in annual maintenance (£1,000 versus £1,300), the Audi RS5 Sportback is the more fuel-efficient choice, a full tank costs around £80 for the Audi RS5 Sportback and £70 for the Porsche 718 Cayman GT4 RS.
Driving Character: Audi RS5 Sportback vs Porsche 718 Cayman GT4 RS
The RS5 Sportback delivers a sophisticated driving experience focused on immense, all-weather pace. Its 2.9L twin-turbo V6 pushes 444 hp, providing a linear and authoritative surge of acceleration that makes the 0-60 sprint feel effortless. The Quattro system, paired with a sport differential, ensures the chassis feels planted and neutral, even in challenging conditions. While it may lack the raw, emotive bark of a V8, the technical precision is hard to ignore. It is a car that covers ground with clinical efficiency, keeping the driver composed and confident regardless of the severity of the road surface.
The Porsche 718 Cayman GT4 RS represents the apex of the 718 platform, transplanting a 493hp naturally aspirated flat-six from the GT3 into a mid-engine chassis. The result is a machine with staggering agility and a turn-in response that makes even the standard GT4 feel soft. The chassis balance is dominated by rear-end grip and sharp, responsive steering that provides constant feedback. It is an extreme instrument, demanding a high level of expertise to truly extract its full potential. The power delivery is frenetic, culminating in a high-revving wail that defines the car's racing-inspired character.
Head-to-head, the division is clear: the Porsche 718 Cayman GT4 RS takes our 0-100 driving character grading, 72 against 96. Characteristic of the Audi RS5 Sportback: Composed, quattro-assured pace with a characterful twin-turbo V6. For the Porsche 718 Cayman GT4 RS: GT3-derived engine in the lightest, most track-focused Cayman ever. In outright terms it is 444 hp against 493 — a 49 hp gap — and the Porsche 718 Cayman GT4 RS reaches 60 mph 0.5s sooner.
Interior & Cabin: Audi RS5 Sportback vs Porsche 718 Cayman GT4 RS
The cabin is a triumph of function and premium finish, centring on the high-resolution Virtual Cockpit. Everything is exactly where a driver would expect it, with high-quality materials and a robust build feel that characterises Audi’s best interiors. The Sportback silhouette does slightly compromise headroom for rear passengers, though the four-door configuration makes it far more accessible than a traditional coupe. It feels intimate yet spacious, balancing a cockpit-style atmosphere with sufficient room for adults. While it shares some architecture with the standard A5, the RS-specific trim and seating elevate the experience to something truly special.
The interior is a study in weight reduction, featuring CFRP door panels, lightweight door pulls, and carbon bucket seats that lock the driver in place. The presence of the standard roll bar behind the seats signals its intent, creating a sparse, motorsport-focused atmosphere. Sound deadening is intentionally minimal, allowing the mechanical symphony—and the roar of the intake located just behind the driver's head—to flood the cabin. It is not designed for luxury or comfort, but rather as an extension of the driving experience, prioritising tactical feedback and material efficiency above all else.
Head-to-head, the division is clear: the Audi RS5 Sportback takes our 0-100 interior & cabin grading, 82 against 50. Characteristic of the Audi RS5 Sportback: Spacious, well-finished cabin with practical 5-door hatch access. For the Porsche 718 Cayman GT4 RS: Stripped-back, motorsport-focused cockpit.
Daily Usability: Audi RS5 Sportback vs Porsche 718 Cayman GT4 RS
Practicality is the RS5 Sportback’s hidden talent, blending high performance with genuine usability. The 480L boot is surprisingly cavernous, and the rear doors make loading children or shopping a non-issue. Its footprint is manageable for urban environments, allowing for relatively stress-free parking. The ride, while undeniably firm when set to Dynamic, remains supple in Comfort, smoothing out motorway undulations effectively. It is a car that thrives on long-distance grand touring, where its stability and power come into their own, yet it remains perfectly at home running mundane errands through a congested city centre.
Daily utility is significantly compromised by the track-oriented nature of the GT4 RS. The suspension is exceptionally firm, making it punishing on all but the smoothest road surfaces, and the lack of sound insulation makes it unsuitable for long, tedious commutes. Despite this, the front and rear trunks remain available for storage, and the inclusion of a front-axle lift system helps navigate urban obstacles. While it is technically possible to drive to the track, the RS experience is best reserved for spirited road use or dedicated circuit days rather than routine errands.
Head-to-head, the division is clear: the Audi RS5 Sportback takes our 0-100 daily usability grading, 85 against 35. Characteristic of the Audi RS5 Sportback: Genuinely practical everyday performance car with a usable boot. For the Porsche 718 Cayman GT4 RS: Usable but clearly built for track days over commuting. that means 480 litres of boot space against 125, plus a usable front boot in the Porsche 718 Cayman GT4 RS, and everyday running costs that favour the Audi RS5 Sportback at the pumps.
Ownership: Audi RS5 Sportback vs Porsche 718 Cayman GT4 RS
Ownership costs for the RS5 Sportback are balanced, leaning towards the premium end of the mid-size performance spectrum. Achieving 30 mpg on a steady run is a welcome benefit of the V6 layout, though enthusiastic driving will see that figure plummet. Servicing intervals are well-structured, though the Quattro driveline does require specific attention to remain in peak condition. Audi’s expansive dealer network is a massive advantage, ensuring that parts and expertise are never far away. Strong residuals and a broad appeal make this a sound financial proposition for a high-performance vehicle, provided you are prepared for the annual maintenance budget.
Owning a 718 Cayman GT4 RS is a high-stakes proposition, with high purchase prices and significant service costs reflecting its status as a low-volume, specialised performance vehicle. Values have appreciated rapidly, as the model occupies a unique space in the modern Porsche lineup. Owners benefit from the comprehensive Porsche Motorsport support network, which is essential for managing RS-specific components that are more expensive and harder to source than standard parts. It is a collector's dream, provided the owner acknowledges the substantial overheads and the demanding nature of maintaining a high-performance track machine.
Head-to-head, the division is clear: the Audi RS5 Sportback takes our 0-100 ownership grading, 78 against 78. Characteristic of the Audi RS5 Sportback: Strong Audi reliability reputation. For the Porsche 718 Cayman GT4 RS: Mechanically simple, Porsche-grade reliability. On the wallet the two diverge at £65,000 versus £115,000 — a £50,000 difference, with annual maintenance of £1,000 against £1,300, and warranty cover of 3yr / unlimited mi versus 4yr / 50k mi.