On first seeing Theon Design’s GBR006 Great Britain commission, I’m reminded of those viral photographs of a supposed time-traveller. Picture a sepia 1940s crowd interrupted by an interloper clutching what looks suspiciously like a smartphone.
This Ice Green Metallic machine plays the same trick. At a glance, the classic proportions and Fuchs-style alloys suggest a beautifully restored Porsche 964 Carrera. The finer details – and the engine’s raucous sound – tell a very different story.
As with the alleged time-traveller, the incongruity doesn’t take long to register. The rear arches are widened and house 18-inch wheels that are more deeply dished than those of a typical 964. The headlight lenses are crisper and the units below a touch slimmer. The iconic Porsche emblem sits flush in the bonnet between them, and a discreet front splitter sits just below.
It’s a striking sight in early autumn sunlight, parked just outside Theon’s Banbury headquarters, in the heart of Motorsport Valley. The family-run firm has been building 964-based restomods since 2019 and builds just five a year for clients across the globe. Staggeringly, each car takes in excess of 6000 man-hours to complete.
A brief tour of Theon’s workshop with company co-founder and former BMW, Lotus and JLR designer Adam Hawley reveals the depth of passion, detail and care poured into each commission. A handful of cars in various states of assembly are being busily worked on by Theon artisans and engineers with fastidious attention to detail. Even the parts a customer will never see are painted and polished to the standard of the exterior panels.
Like the cars being assembled, GBR006 began life as a donor 964 – a 1993 model in this case. Adam takes some satisfaction in giving tired, neglected 911s a second life, and says he’d refuse a donor if it were too good an example to subject to the surgery involved.
First, the donor is stripped to bare metal, 3D-scanned and straightened to factory specification – these chassis tend to sag with age. The structure is then seam-welded to deliver greater strength and rigidity than the period production line could provide.
From here, options are almost endless, from carbonfibre bodywork to a supercharged flat-six. GBR006’s owner ticked the former, specifying muscular RS-style carbonfibre panels that remove around 100kg from the kerbweight. The steel-skinned factory doors are retained for their side-impact protection and that satisfying OEM ‘clunk’ when they’re slammed shut. The bodywork is finished in Ice Green Metallic paintwork – an original Porsche colour – with ghosted stripes and Polished Eclipse Chrome brightwork completing the look.
Porsche engine bays aren’t typically known for their aesthetic appeal, but open GBR006’s lid and you’ll find an impeccably presented Mezger flat-six. A triumph of minimalism, Jenvey independent throttle bodies rise from each cylinder bank above the carbon-shrouded cooling fan into a beautifully finished wire-gauze plenum.
The minimalism is partly down to relocating the power-steering pump and air-conditioning compressor to the front, which contributes to the improved weight distribution (38:62 to 48:52) and sharper handling balance. Similarly, Theon has installed an aerospace-spec engine wiring loom that now connects via a single plug, improving serviceability and saving a further 30kg. Adam tells me that while the OEM loom is packing-crate huge, Theon’s version practically fits within a Jiffy bag.
Unsurprisingly, the attention to detail continues with the engine mechanicals. Originally a 3.6-litre air-cooled flat-six from a 964 Carrera, Theon has increased capacity to 3.8 litres with upgraded cylinder heads. Racier cams, lightweight forged internals, that elegant intake plenum and a MoTeC ECU with switchable maps see it deliver 407bhp and 293lb ft to the rear wheels via a five-speed manual transmission. At 107bhp per litre, it’s the highest specific-output Theon engine to date.
Fling open the driver’s door and you’re greeted by a cabin that mirrors the polish of the engine bay and exterior. Porsche’s classic ‘tombstone’ seats have been swapped for carbon-backed Recaro CS buckets trimmed in Phantom black leather with exterior-colour-matched Ice Green stitching. Every surface and touchpoint is exquisitely finished, from the Alcantara- and leather-trimmed seats, dashboard and reshaped door cards to the OEM switchgear and vents remanufactured in billet aluminium.
Theon has fettled and refined everything you see, yet from behind the wheel it still feels like a classic 911. The upright windscreen and thin pillars give excellent visibility. The control layout is exactly as Stuttgart intended, while the custom dials add a subtle bespoke touch. The only drawback is the floor-hinged pedals, whose slight offset to the left leaves nowhere to rest your clutch foot.
GBR006 feels like a classic 911 on the move. Meandering through the villages of rural Oxfordshire, the flat-six behaves exactly as you’d expect and is surprisingly quiet and refined for such a highly strung unit. The five-way TracTive dampers are equally impressive, compliant and well judged for the cratered roads of provincial England, while reining in body roll in the more aggressive settings.
It’s only once you reach a quiet, serpentine stretch of British B-road that Theon’s handiwork truly makes itself known. While 407bhp is hardly a headline-grabbing figure these days, the 1150kg kerbweight means the car has a power-to-weight ratio of 353bhp per ton, nudging past a 600bhp Nissan R35 GT-R Nismo.
This feels like the ideal level of performance for a road car, aided by the linear delivery of a naturally aspirated engine. The other payoff is its razor-sharp response and the intoxicating metallic howl as the needle nears the 7600rpm redline – especially with the exhaust baffles open. Then, dip the clutch, enjoy the tactile gearchange and listen to the engine’s melody all over again.
The engine is certainly exciting – and its soundtrack is incredibly addictive. Crucially, it’s matched by a confidence-inspiring chassis, feelsome hydraulic steering and progressive 993 Carrera RS-spec brakes with ample stopping power.
In many ways, Theon Design’s latest creation is Porsche 911 nirvana – timeless looks, an impeccable level of finish and detail, and an emotive, analogue driving experience paired with lightness and just the right level of potency for modern roads. The only catch is the price – as commissioned, GBR006 cost £420,000 to build, plus the donor car.
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