People who know MX-5s know that they’re not about the stats, but more about the sensations of driving, the rear-set seating position, compact cockpit, the stubby yet perfectly placed gear selector, near-50:50 weight distribution, and the fabulously communicative steering. The car has never troubled the upper echelons of the power output league tables, because it hasn’t needed to for most drivers; the sensation of speed is as much of a thrill as outright speed in this car.

But what if you could take all that, and make it about the numbers? While the humble roadster has many established tuning options, it somehow hasn’t gained the same tuner icon status as the Honda Integra, Nissan GT-R, or A80 Toyota Supra. The third-generation NC roadster is brilliant to drive as Mazda intended, but what happens when one goes beyond Mazda’s remit?

It’s a question the owner of this particular car, Ellis, was determined to answer. To realise his vision he teamed up with BBR, an MX-5 fettler who needs no introduction. The specification does however, as powering his NC is a 2.5-litre Ford Duratec crate engine producing 260bhp and 230lb-ft (312Nm) of torque.

Supercharging is normally BBR’s default route to such an output. But Ellis wanted to preserve the progressive power delivery of a naturally aspirated engine, creating a capable and usable car that’s rewarding on B-roads and circuits, while keeping the all-important - and much loved - character intact.

Naturally, being one of us, there was far more to it than a straightforward engine transplant. The new 2.5-litre block gained forged internals before being mated to the original 2.0’s cylinder head, itself having been ported and polished, and endowed with spicier camshafts, plus larger valves. But what really matters about this engine is the breathing - four individual throttle bodies on the way in, and a BBR manifold and Sports Touring exhaust system on the way out.

You wouldn’t know about this NC’s potential from a quick glance though. This dark grey NC sits low, its arches shrink-wrapped over a set of OZ Racing wheels wearing Michelin Pilot Sport 4 rubber. The front bumper retains the clean look the model launched with in 2005, but the foglights have been replaced with ducts feeding air to the factory-spec discs, now gripped by EBC pads. At the rear, a subtle ducktail spoiler and twin exhaust tips hint at what lies beneath.

Contrasting the subtle tweaks to the exterior, the cabin takes on a whole new race-inspired personality. Fixed Sparco bucket seats feature four-point harnesses, and once secured I can clasp the alcantara rim of the deep-dish Momo steering wheel. This and the alloy gear selector feature cut-out sections to make them look as light as they feel in my hands.

The view out looks very familiar, but as soon as the 2.5-litre engine bursts into life it's clear this will be a far more intense experience than anticipated. Four-cylinder engines have never been renowned for their smoothness, but with the seat bolted firmly to the chassis, the miniscule vibrations post-fast-idle are detectable through my spine. It’s not as if the engine feels shaky, but rather alive, keen to get moving, and to show me what it can do.

With only a negligible amount of weight added during its rebuild, the sub-1,150kg roadster is effortlessly brought up to speed on a gentle throttle, the raspy exhaust finding its voice from 2,000rpm. The larger-displacement engine is tuned to be leant on rather than wrung out - ask for more and the tone changes as the throttle bodies open wide, the Duratec hitting its mid-range torque peak with urgency.

The NC immediately feels at home on tree-lined lanes, needing only slight steering inputs to flow through sweeping bends. The variable-ratio steering sharpens above 40mph - directional changes require barely a degree of lock. Commit to a line and the car rewards you, its weight distribution and mechanical grip carrying it through corners with confidence.

Above 30mph, the adjustable HKS coilovers also begin to find their stride. At anything below they’re firmly sprung, but once clear of the threshold the car sits flat through corners, tilting only to follow the road's camber. Body roll is virtually non-existent.

As the bends tighten, the BBR can move quickly and decisively, feeling as planted yet light on its feet as a helium-filled Shetland pony. The brakes are more than capable for fast B-road work, a mix of engine braking and trail-braking taking care of most of the slowing; pushing beyond a third of the pedal's travel feels like an emergency stop. The car revels in conserving momentum, and with the Quaife limited-slip differential shuffling power side-to-side, I can fine-tune my line through corners using throttle alone.

In most modern cars, a mechanical LSD works in tandem with the car’s traction and stability control systems, but here the combination of increased engine output and a new ‘diff is too much for the Mazda’s brain to comprehend. As a result, the car must be driven with the electronic driver aids switched off, or else it’ll go into limp mode as soon as the Quaife hardware begins marshalling the power as it sees fit. If there is one tell this car is a project build, this is it. For some, the lack of a safety net could temper enthusiasm.

Despite the 50 percent increase in power and torque, the chassis handles it all - the fundamental architecture is that good. A large part is also the progressive nature of the power delivery. The calibration of the throttle bodies is so precise and sensitive, even millimetric movements of the right foot provoke a response. 

But for the best demonstration of the 2.5-litre engine’s breadth, it’s best to slot the chunky gear selector into second, and roll-on from 1,250rpm. With a few loose stones on the Dartmoor tarmac, the car wiggles ever so slightly as it flicks the gravel away and secures its footing. The initial swell of torque at 2,000 revs builds to become a surge by 4,000rpm, the throttle bodies generating a dry, motorsport-inspired, bark. The balance of intake and exhaust noise shifts rearwards as the engine reaches its 6,000rpm power peak, and while there’s no need to keep the needle rising to the 6,500rpm red line, it’s worth it for the audible crescendo alone.

A satisfying shift into third drops the engine back into its peak torque range, before heading towards the rev limiter with haste once again. Rather than slamming the pedal to the floor, and yanking the gear selector between notches, the car asks for smoothly decisive inputs, and offers an exceptionally broad biting point. The gearbox finds the next ratio smoothly, without the mechanical snatch of a harder-edged setup. Gently blending the power back in is a must to ensure a seamless shift whether going up or down through the box. The pedals are also perfectly spaced for some heel-and-toe action, should you be inclined.

Keeping the throttle pinned to the floor, the race-ready soundtrack drowns out the rush of the airflow overhead, amplifying the sensation of speed as the next corner quickly beckons. Sticking in third, I lift off the accelerator, hear a surprising but natural pop coming from the pipework behind me, and ever so gently trail-brake towards the bend. While the revs to drop it down into second are available, I instead leave the car in gear and lean on its low-range grunt to pick up the pace again, and enjoy the strong but smooth torque peak as it carries me briskly along the next straight.

The car is in its natural habitat floating through sweeping bends and attacking switchbacks. I quickly learn to judge pace by engine note and gear selection alone, trusting the car's momentum. The rate of advancement in all settings is higher than it would be in a stock NC, of course, but every other sensation of driving has been amplified proportionally, delivering one hell of a thrill behind the wheel.

Therein lies the magic of this particular example. Despite having a new engine, cams, throttle bodies, forged connecting rods, exhaust system, suspension set-up, wheels, tyres, brake pads and lines, bucket seats, harnesses, steering wheel, gear selector, pedals, and a bare-metal rebuild of the subframes, this car still retains the characteristics of the NC MX-5 at heart, but it can offer far more than a standard model could.

The real-world performance is absolutely right for a car of this size, and for the roads where it is designed to excel. The car now has the output to make overtaking a breeze, and to keep up with the best modern hot hatches through corners and along straights alike. The suspension delivers balance and poise that punches well above the car's weight. The steering wheel and gear shifter are a joy to use, as communicative as the precisely weighted, spaced, and sprung pedals.

Perhaps best of all, to the untrained eye it still looks like an MX-5 despite its extensive modifications. It hides in plain sight, only drawing glances when its four throttle bodies sing in unison, before swiftly vanishing from view. The downsides? You won’t have a chance of reaching the pedals if you’re under 6’ tall, hitting potholes or drains can feel violent at lower speeds, and there’s no cruise control to take the sting out of a track day commute.

This is a car designed to be precisely controlled by its driver, and when piloted in a swift and smooth manner, it comes together perfectly. Curiously, Mazda never made an in-house performance variant of the NC, but this BBR-tuned example built to meet the exact desires and measurements of its owner showcases what the car is capable of, and realises the potential of the chassis. If there were to be such a thing as an MX-5 Spirit R, there would be no better blueprint.