Unleashing serious cornering ability, our Porsche Cayman GT4 upgrades have impressed during countless trackdays. With much wider tyres beneath standard bodywork, our development GT4 is lapping circuits faster than ever.
Our groundbreaking ‘Stage 2’ rear camber plates continue to make big waves on the Porsche scene. These parts allow the fitment of 325-width rear tyres (+30mm over stock) to the Cayman GT4 and GT4 RS, and Spyder RS with zero changes to bodywork required.
Combined with our front top mounts, which allow the fitment of 265-section front tyres (+20mm), these Porsche models can now utilise the same width footwear as the incredible 991-series GT3 RS.
Development and testing of our Porsche rear top mounts began in early 2025, with professional racing drivers undertaking serious road and track work to ensure reliable performance from our parts.
More than 20 trackdays and thousands of miles later, and our most ambitious Porsche suspension upgrades yet are still going strong on our 718 GT4.
Watch This Space
There are in fact two versions of our rear top mounts for the GT4, GT4 RS and Spyder RS – and like all Suspension Secrets upgrades they’re designed and manufactured entirely in-house.
The Stage 1 rear camber plates provide enough clearance for 305-width tyres and serve as a perfect halfway house for owners looking to increase rear grip over the stock setup. Our Stage 2 rear top mounts (pictured above) are a more extreme upgrade and must be teamed with our adjustable rear toe arms and shorter rear main springs (170mm) to make the fitment of 325-section tyres possible.
Although entirely usable on the road, the main purpose of our Stage 2 rear top mounts is to dramatically enhance on-track handling performance. Both our Stage 1 and Stage 2 top mounts are compatible with a range of aftermarket coilover systems, as well as the factory dampers, ensuring maximum flexibility for owners around the world.
So, how do they work? The Stage 1 rear top mounts feature an offset bearing position, which dictates how the dampers are installed. The additional angle created by the top mount’s offset bearing position means the damper unit is tilted more inboard.
This repositioning of the shock absorber creates more clearance for wider tyres. You can then set more negative camber using the stock camber adjustment on the lower control arm; for more aggressive camber settings we recommend installing our adjustable rear toe arms.
Our Stage 2 rear top mounts take things a step further. Their taller, two-piece design features an even greater bearing offset, which pulls the damper strut further inboard than the Stage 1 parts. This creates even more clearance for an even wider 325-section tyre – all while maintaining the standard bump-to-droop ratio.
Wheels and Setup
With still limited space inside the rear arches of the GT4, GT4 RS and Spyder RS, wheel size and suspension setup are key to making the entire package work as intended.
After careful calculations, we opted for alloy wheels in size 20×9.5J ET52 on the front axle of our GT4, and size 20x12J ET45 wheels at the rear – all shod in Michelin Pilot Sport Cup 2 tyres. We understand that sourcing wheels in these sizes can be challenging (our GT4 is equipped with Bola CSR rims), so we can confirm 19-inch wheels with the same widths and offsets work perfectly as well.
The car’s ride height also plays an important role in the application of our Stage 2 rear top mounts. To help owners with suspension setup, we provide a geometry sheet with every Suspension Secrets parts purchase tailored to your vehicle’s specification and intended use.
It’s undoubtedly a bonus that the Porsche Cayman GT4 and GT4 RS, and Spyder RS all feature front and rear ride height adjustment as standard, which makes adjustments easier – and less costly.
Track Performance
During development of our Stage 2 rear top mounts, we anticipated the improvement they would bring to handling performance would be substantial, and so it has proven. Our 718 Cayman GT4 is now generating so much grip that it’s setting practically identical lap times to a 991 GT3 RS despite its lesser levels of downforce and six-speed manual gearbox.
With the Stage 2 Kinematics Kit installed, our GT4 shaved approximately three seconds from its previous best lap time around Donington Park’s 2.49-mile GP Circuit (1min 39.5sec). Highly experienced drivers have also praised our GT4 for its dramatically improved stability, fine chassis balance and sheer fun factor.
On that front, our 718 GT4 remains an incredibly user-friendly sports car. Thanks to the additional negative camber dialled into the chassis with Suspension Secrets top mounts and other upgrades, our GT4 is using its tyres much more effectively – in terms of both grip generation and wear rate. That means only great things for lap times and tyre budgets.
Porsche Upgrades
As we have shown, it’s possible to compete with much more expensive and higher powered cars using Suspension Secrets upgrades on Porsche’s fantastic 981/718 platform.
Our front and rear Porsche top mounts complete our Circuit Handling Pack and allow owners to fit much more aggressive tyre sizes to their GT4, GT4 RS and Spyder RS.
Our Porsche Kinematics Kit will also provide a great foundation for the aerodynamic upgrades coming soon to our GT4. As always, we’ll keep you updated on developments via our social media and YouTube channels.
