Theon Design has revealed its latest bespoke Porsche 911 (964) commission, codenamed GBR003 – the company’s debut open-top Targa model.
As with every Theon Design commission, the all-carbon bodied, six-speed manual, 4.0-litre naturally aspirated GBR003 is an entirely bespoke creation, enhanced from the ground up at Theon’s production facility, nestled in the heart of Oxfordshire’s ‘motorsport valley’.
Finished in a one-off, paint-to-sample Pastel blue, over liquorice leather, the Targa is the ultimate realisation of a client’s Porsche 911 fantasy, combining OEM+ design and engineering capabilities, hand-crafted luxury touches, with cutting-edge technology and manufacturing processes.
GBR003 is executed with Theon’s customary obsessive attention to detail and laser-focused engineering rigour, resulting in a car that delivers the sensory thrills of open-top motoring without any dynamic compromises.
To ensure the Targa drives with signature Theon fluidity and control, the team has developed a system of bespoke carbon fibre strengthening ‘tubs’, which are bonded to the floor of the chassis, significantly improving torsional rigidity while keeping additional weight to the absolute minimum.
GBR003 takes a Porsche 911 (964) Carrera 2 Targa as its base. The donor car has been stripped back to bare metal before being meticulously restored over thousands of hours by Theon’s passionate technicians.
The body for GBR003 is all-carbon, aside from doors which remain steel for side impact protection. As with all Theon builds, each panel has been digitised and modelled in 3D design software to ensure a perfect fit. Thanks to the carbon panels, and the use of carbon for the underfloor strengthening, GBR003 weighs in at just 1228kg with all fluids on board, a mere 60kg more than the equivalent Theon coupe.
A bespoke carbon fibre bracing system ensures exemplary underfloor strengthening. The innovative, lightweight solution transforms structural rigidity without adding any undue additional weight – using the same carbon construction technology deployed in Formula One and other forms of elite-level motorsport.
The strengthening system takes the form of two ‘tubs’, created using a laminate ‘sandwich’ of toughened epoxy prepreg carbon fibre and aerospace-grade Nomex honeycomb—conceived to be as strong and light as possible. The tubs are first designed in CAD to perfectly fit the floor of the Targa chassis before being formed to the tightest tolerances using a 5-axis CNC machine.
No stone was left unturned in the pursuit of total rigidity, with the carbon laminate orientation and thickness optimised through CAD structural simulation software to ensure the stiffest possible construction. Once fabricated, the tubs were permanently bonded to the existing chassis and bulkheads to deliver maximum driving stability, even in the most demanding conditions.
Theon’s signature, laser-focused attention to detail is evident in all areas of the build – even those elements housed and hidden deep beneath the car’s carbon fibre skin.
Every element is honed and enhanced to perfection. For instance, an aerospace-grade wiring loom snakes beneath the sculpted body – saving over 20kg, while modern dual air-conditioning compressors, and an all-new electro-hydraulic power steering pump are relocated to the front of the car, tucked low down to aid the 48:52 front to rear weight distribution.
Then there’s the GBR003’s air-cooled beating heart, a 4.0-litre flat six masterpiece. Featuring independent throttle bodies and breathing through dramatic open trumpets, the motor produces 403bhp at 7100 rpm – breaking through the hallowed 100bhp per litre barrier. It remains entirely tractable, with peak torque of 320lb/ft at 5500rpm. Combined with its low kerb weight, the GBR003 always has deep reserves of performance, surging effortlessly towards the horizon whatever the engine speed or gear.
Exploring the upper reaches of the rev band reveals a more savage side to the engine’s character; it pulls with sheer ferocity all the way to the limiter, building power all the way. This unyielding thrust is accompanied by a stunning flat-six howl from the latest iteration of Theon’s custom, switchable and fully ceramic-coated exhaust – rendered all the more life-affirming when the roof is removed.
The updated, bespoke exhaust system gives GBR003 a quieter, more reserved character in normal use, then offering a full motorsport style flat-six cry when the valves open. The valves can be activated manually via a switch in the cabin, and also open automatically when pushing on into the rev range.
With a lightweight, single-mass flywheel, GBR003 has near-synaptic throttle response, while the slick six-speed manual gearbox – built to 993 RS specification is a sheer joy to row up and down, with carefully repositioned pedals inviting you to heel-and-toe when downshifting – if only to hear the flat-six motor sing.
Thanks to a power-to-weight ratio of 328 bhp per ton – the same as a 991 GT3 – outright performance is modern supercar quick, with a full 993 RS brake setup providing exemplary stopping power.
Autobrief snippets
- Theon elevates open-top air-cooled Porsches to new heights with bespoke 911 Targa
- Fully restored and enhanced from a 964 donor, built to precise customer specification
- Features innovative carbon fibre chassis strengthening system for coupe-like stiffness
- Lightweight carbon body, 403bhp, 4.0-litre air-cooled flat-six, six-speed manual ‘box
- Ultimate stopping power through 993 RS brakes; transformed dynamics thanks to
five-stage adaptive TracTive dampers - Showcases Oxfordshire-based Theon’s OEM-grade design and engineering expertise