A $60,216 Manthey Performance Kit turns the Porsche 718 Cayman GT4 RS into a weapon on the Nürburgring Nordschleife, where the track’s reputation as the “Green Hell” is earned. The kit—now only available on discontinued models—was tested in a 2026 Cayman GT4 RS, a car Porsche stopped producing in February 2025 as part of its shift to electric entry-level sports cars. The decision left enthusiasts scrambling, but for those who still own one, the Manthey upgrade delivers results that defy expectations.
The kit’s development began near the track itself. Manthey, a race team founded in 1996 by Olaf Manthey, opened its first permanent shop just outside the village of Meuspath, near the Nürburgring. Today, the original facility is surrounded by performance testing centers for brands like BMW, Mercedes-AMG, and Hyundai. Porsche acquired a 51% stake in Manthey in 2013, expanding its role beyond motorsport into road car tuning. Unlike AMG, which modifies engines, Manthey focuses on suspension, aerodynamics, and lightweighting, transforming Porsches into track-ready machines without touching the powertrain.
Results speak for themselves. In 2023, former Porsche factory driver Jörg Bergmeister set a 7:03.121 lap in a Manthey-equipped 911 GT3 RS, a time just 0.8 seconds slower than his run in a 911 Turbo S, a car with 138 more horsepower and all-wheel drive. The Cayman’s compact size and 11.0-second quarter-mile time (just 0.1 second slower than the GT3 RS) make it a sleeper. On the Nürburgring, where the 911’s extra power counts for little in the twisty sections, the Manthey Cayman holds its own, proving that aerodynamics and chassis tuning matter as much as horsepower.
How the $60K Kit Transforms Handling
The kit’s $60,216 price tag breaks down into tangible upgrades. Aerodynamics receive the most attention: a carbon-fiber front diffuser, adjustable rear wing (with four angle settings), and front flaps increase downforce at 124 mph from 196 pounds to 372 pounds. The rear wing alone is 3.4 inches wider, reshaped to match the GT4 RS’s roof line and improve airflow. Suspension gains 20% stiffness at the front axle via adjustable coil-overs with aluminum dampers, while steel-encased brake lines sharpen pedal response. European models include copper-sintered brake pads, though U.S. laws restrict their sale as part of the kit.
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One detail stands out in testing: the car’s confidence under braking. The Manthey kit’s stiffer setup and quicker brake response let drivers push harder into corners like Aremberg and Bergwerk, where high-speed sections demand precision. The 170+ mph exit speed through Döttinger Höhe, one of the few flat-out stretches on the Nordschleife, feels effortless, masking the Cayman’s smaller engine. The trade-off? Keeping the 4.0-liter flat-six in its 7,000–9,000 rpm sweet spot requires constant attention, but the kit’s balance makes it forgiving.
The Manthey 718 Cayman GT4 RS isn’t just faster; it’s more approachable than a stock GT4 RS. Where the base model struggles with grip and balance, the kit’s adjustments make it feel like a 911 GT3 RS in spirit, if not in power. Even the illuminated carbon door panels hint at the kit’s track-focused philosophy: every change serves a purpose.
Track Adaptability in Wet Conditions
The damp sheen on the Nürburgring’s tarmac didn’t just test the car’s grip; it exposed the Manthey kit’s ability to adapt. Where a stock GT4 RS might have wallowed in the mist, the stiffer suspension and quicker brake response allowed the driver to trust the car’s limits. The Michelin Pilot Sport Cup 2 tires, designed for track use, gripped the slick surface better than expected, though the driver still caught glimpses of the guardrail at Bergwerk. The car’s balance made recovery feel natural, not forced, a trait Manthey engineers prioritize in their development.
One of the kit’s less obvious but critical upgrades was the steel-encased brake lines, which eliminated the spongy pedal feel common in high-performance Porsches. The copper-sintered brake pads, available in Europe but restricted in the U.S., would have further sharpened stopping power, though even without them, the Manthey Cayman’s braking felt more decisive than the stock model’s. The adjustable rear wing, set to its highest angle, generated enough downforce to keep the car planted through the Karussell’s tight left-right sequence, where a misstep could send it into the trees.
