Audi RS6 Avant vs Porsche 718 Cayman GT4 RS
Compare the Audi RS6 Avant vs Porsche 718 Cayman GT4 RS. The Porsche 718 Cayman GT4 RS is £0 cheaper. The Porsche 718 Cayman GT4 RS is 0.1s quicker to 60mph. The Audi RS6 Avant is more fuel efficient. Full performance, cost & ownership breakdown.
The Audi RS6 Avant is priced from £108,000, powered by a 4.0L Twin-Turbo V8, producing 591 hp, with 800 Nm of torque, reaching 0-60 mph in 3.5s, a top speed of 190 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 RS6 Avant offers a 565-litre boot, folding rear seats, runs on petrol, returns around 24 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 Porsche 718 Cayman GT4 RS is £0 cheaper than its rival, the Audi RS6 Avant costs less in annual maintenance (£1,100 versus £1,300), the Audi RS6 Avant is the more fuel-efficient choice, a full tank costs around £90 for the Audi RS6 Avant and £70 for the Porsche 718 Cayman GT4 RS.
Driving Character: Audi RS6 Avant vs Porsche 718 Cayman GT4 RS
The RS6 Avant is the definitive super-estate, wielding a 4.0L twin-turbo V8 that delivers 591 hp with crushing authority. Its Quattro system and all-wheel steering work in tandem to shrink the car’s perceived size, allowing it to navigate complex B-roads with surprising ease. The power delivery is immediate, bolstered by mild-hybrid assistance that masks any hint of lag. It is a master of cross-country velocity, offering a level of grip and composure that remains unmatched in the sector. While the 4575 lbs mass is present, the chassis balance is so well-sorted that it never feels overwhelmed or ponderous.
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, 75 against 96. Characteristic of the Audi RS6 Avant: Composed, quattro-assured pace rather than outright playfulness. For the Porsche 718 Cayman GT4 RS: GT3-derived engine in the lightest, most track-focused Cayman ever. In outright terms it is 591 hp against 493 — a 98 hp gap — and the Porsche 718 Cayman GT4 RS reaches 60 mph 0.1s sooner.
Interior & Cabin: Audi RS6 Avant vs Porsche 718 Cayman GT4 RS
The cabin is a sanctuary of technology and luxury, defined by the high-definition Virtual Cockpit Plus and exquisitely finished Valcona leather. Every surface speaks to Audi's commitment to quality, with supportive sports seats that hold the driver firmly during high-speed cornering. The interior design is sophisticated, blending sharp, angular lines with an understated elegance. Despite being a tech-forward environment, the ergonomics remain intuitive, ensuring that even complex adjustments are simple to perform. It is a space designed for long journeys, offering a sense of calm and control, even when the engine is under full load.
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 RS6 Avant takes our 0-100 interior & cabin grading, 85 against 50. Characteristic of the Audi RS6 Avant: Spacious, airy, premium cabin with excellent tech. For the Porsche 718 Cayman GT4 RS: Stripped-back, motorsport-focused cockpit.
Daily Usability: Audi RS6 Avant vs Porsche 718 Cayman GT4 RS
Practically, the RS6 Avant is unrivalled as a high-performance family carrier. With 565 litres of boot space, which expands significantly when the seats are folded, it is ready for almost any task. The air suspension is a revelation, offering a plush, compliant ride for family trips while firming up instantly for spirited driving. Its wide body can be a liability in tight car parks, making the camera system a mandatory tool for urban navigation. However, the sheer ease with which it traverses miles in total comfort makes it an exceptional candidate for a single-car garage.
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 RS6 Avant takes our 0-100 daily usability grading, 92 against 35. Characteristic of the Audi RS6 Avant: Genuinely does everything — family transport, luggage and supercar-embarrassing pace. For the Porsche 718 Cayman GT4 RS: Usable but clearly built for track days over commuting. that means 565 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 RS6 Avant at the pumps.
Ownership: Audi RS6 Avant vs Porsche 718 Cayman GT4 RS
Owning an RS6 Avant is an investment in unparalleled capability, though one must account for the significant running costs. With 24 mpg fuel economy and the wear associated with moving such high performance, it is not a cheap car to run. However, the Audi dealer network is top-tier, and the vehicle enjoys strong residual values, with enthusiasts constantly hunting for well-maintained examples. The annual maintenance costs are predictable for the segment, and the car's widespread support ensures longevity. For those who can stomach the fuel and service bills, it offers a level of excellence that is difficult to replicate.
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 Porsche 718 Cayman GT4 RS takes our 0-100 ownership grading, 72 against 78. Characteristic of the Audi RS6 Avant: Widely reported as a genuine daily joy to own. For the Porsche 718 Cayman GT4 RS: Mechanically simple, Porsche-grade reliability. On the wallet the two diverge at £108,000 versus £115,000 — a £7,000 difference, with annual maintenance of £1,100 against £1,300, and warranty cover of 3yr / unlimited mi versus 4yr / 50k mi.