The Volvo C30 has become the latest model to join the Swedish car maker’s fledgling performance range, following the limited-numbered Volvo S60 Polestar released late last year.

Briefly, the little blue badge next to the Volvo C30 ‘T5′ engine designation indicates the work of Polestar, a Swedish company endorsed by Volvo Car Corporation with many years experience in the racing industry, including building cars to compete in the World Touring Car Championship (WTCC) and Sweden’s own Swedish Touring Car Championship (STCC).

In short, they know their stuff.

What this means for the Volvo C30 T5 R-Design is a retuned engine control unit (ECU), altered throttle mapping and an increase in turbo boost pressure that sees more power, more torque, and faster acceleration, all without any negative impact on fuel consumption (still 8.7 litres per 100km; 9.4L/100km automatic), CO2 emissions (unchanged at 208 grams per kilometre; 224g/km automatic) or Volvo’s factory warranty (three-year unlimited kilometre).

Tuned to produce 184kW of power and 370Nm of toque (up 15kW and 50Nm), the super strong and impressively flexible turbocharged 2.5-litre five-cylinder engine is a joy to be in charge of.

Once shared with Ford (for models such as the blistering Ford Focus RS), the engine provides solid pulling power from below 2000rpm, deep into the rev band.

The boosted Polestar tune helps drop the Volvo C30 T5 R-Design’s 0-100km/h sprint time to 6.3 seconds for the six-speed manual, and 6.8 seconds for the five-speed automatic transmission – an improvement of 0.4sec and 0.3sec, respectively.

Despite Volvo saying the Polestar tune doesn’t affect the C30′s lust for fuel, on the road this simply isn’t true, as the motor feels so good you’re far more inclined to bury your right foot – we averaged 12L/100km with the addictive powerplant entirely to blame.

Unfortunately the Volvo C30 T5 R-Design’s handling dynamics and brakes are significantly less fun to play with.

While around town the car is easy enough to live with – with the exception of its monstrous turning circle that inevitably sees U-turns morph into three-point turns – the Volvo C30′s very light clutch, light steering, dull brakes and noisy, slack gearbox don’t inspire much confidence.

And given the Volvo C30 T5 R-Design’s $43,490 ($44,490 for the auto) asking price, this thing should be a sharp tool, keen to chew up winding roads and upset Volkswagen Golf GTI owners along the way.

Give the Polestar-tweaked T5 engine some beans when out on the twisty stuff and the five-cylinder responds with tail-wagging excitement – it’s like saying the word ‘walk’ to a Jack Russell.

Sadly, however, it fast becomes apparent that the rest of the car simply can’t maintain the same level of performance.

The car is easy to wheelspin on take-offs, understeers when challenged through corners, and while it does change direction easily enough – despite the Volvo’s huge steering wheel and 1388kg – the brakes leave you wondering if Volvo simply let Polestar tune the engine and then did very little else.

All Volvo C30 T5 models – R-Design included – come standard with what Volvo, somewhat ambitiously, calls Dynamic Chassis.

There is an $800 optional Sport Chassis package, which lowers the car 10mm, stiffens the springs 30 per cent and includes specially adapted shock absorbers, stiffer bushings, sport-tuned front and rear anti-roll bars and a higher steering gear ratio, but this was not fitted to our test car, with the resulting disappointment hard to ignore.

The subtle R-Design kit and 18-inch alloy wheels look sharp while keeping the Polestar modifications under wraps.

The car’s fit and finish is right up there with market leaders Audi and Volkswagen, with the interior looking and feeling Volkswagen Group-esque but different in its own Swedish way.

The white-stitched R-Design seats, front and rear, look terrific and feel great, with the driver’s power seat also easy to adjust into a good driving position (adding an identical power passenger seat is another $2075).

The mechanism for bringing the front seats forward to allow access to the rear seat, however, is troublesome to say the least. Locking the backrest into place once forward, locking the seat into the wrong position and sometimes not sliding forward correctly. It’s not ideal in a car with only two doors.

The interior feels open and spacious with the long rear windows providing plenty of light and vision, which also helps when parking – even though it does have parking sensors that you can deactivate from the ‘control stalk’.

The Volvo C30 T5 R-Design’s stereo has serious kick too. Our test car had the standard High Performance Sound eight-speaker system that’s so impressive, it’s a struggle to imagine justifying the $1425 for the optional 10-speaker Premium Sound unit.

All the buttons feel good and are nice to touch and push but the unit itself looks terribly dated.

The dash instruments are clear and easy to read – if a little subdued – and the electronic display that shows fuel consumption, trip computer etc is illuminated in very 1980s green block lettering.

The handbrake is on the ‘wrong’ side, which although initially annoying, is something you’d get used to, much like the ignition being located atop the centre console on the driver’s left-hand side.

The lack of a footrest, however, would never cease to annoy.

Storage spaces are limited with only door pockets and two centrally located cup holders near the gearlever, the latter proving to be sublime for holding phones.

The secret space behind the ‘floating’ guitar-string design centre stack is a bit tricky to reach and usage comes with the fear of forgetting you put something there as it remains out of sight.

While the small rear glass-hatch is a key design cue for the Volvo C30, it means the boot aperture is narrow, reducing access, though once loaded up, a surprising amount of gear can be ingested.

The Volvo C30 T5 R-Design tuned by Polestar is a solid package that delivers some additional performance and fun but in the end it’s a car that struggles with the two key elements of being a proper hot hatch, performance and practicality.