Muscle cries for more focus

Hairdresser Syndrome. It is something that has been plaguing small roadsters for years.

Just look at the Mazda MX-5. Lovely machine, fabulous to drive, but tell anybody that you have the keys to one and they'll suddenly start eyeing you out with suspicion.

Of course you'll be quick to defend your purchase by spurting out words like 'balance,' 'purist' and 'feedback' but by then it will be too late: in the minds of Joe Public you may as well be hanging out at Terenzo with a limp wrist, a comb and a crushed silk shirt.

It's a common and often demeaning automotive affliction - one that has led to most of the world's vehicle manufacturers cooking up a fairly simple inoculation: raw power.

Indeed, by simply turning up the wick, icons like the Lotus Elise S, Honda S2000 and Porsche Boxster S have proved that going topless need not result in a life of ridicule. It is fail-safe immunity, and probably the reason why Audi has joined the fray with their radical TT-RS roadster.

For unlike every other TT that has come and gone before it, this mean mother ups the ante with one hell of a special engine. A homage to the mechanical animal that once gave the Quattro S1 rally car such a fearsome reputation back in the '80s, the heart of the TT-RS beats to the rhythm of five-cylinders force-fed by a whacking great turbocharger.

Tuned to deliver a healthy 1.2 bars worth of boost and complemented by a direct fuel-injection system that ensures maximum petrol bang for your buck, all this adds up to the most powerful Audi TT roadster ever produced. Even in the greater sports car scheme, coupés included, on-paper figures of 250kW and 350Nm demand a certain degree of respect. So too does that formidable 0-100 sprint time of 4.4-seconds.

Of course bold performance claims are one thing, but even out in the streets of the real world the TT-RS feels biblically fast.

In fact I would be really surprised if, at Johannesburg altitude, it does not give its bigger and dearer sister, the R8 V10 Spyder, a run for its money.

Blisteringly quick out of the blocks - especially when you utilise the launch control mode native to the optional S-Tronic gearbox - it just keeps on pulling until the top-speed nanny intervenes when the speedo needle tickles the 250km/h mark. Seriously, the whole business of building furious forward momentum seldom gets easier, or more accessible, than this.

It's an admirable characteristic for Audi's engineers to have massaged into the TT-RS, I'll admit, but one that can also get you into all kinds of legal trouble should you not keep tabs on what your throttle foot is doing. Easier said than done because to feel truly involved in the driving experience, you're constantly looking for ways to push this roadster to its seemingly unbreakable limits. If you don't, it's difficult to not be somewhat underwhelmed, especially in the twisty bits.

Unlike the old RS4 that could swing hips with the best of them, this range-topping TT-RS comes across as being far too neutral when you finally get to unleash a little driving anger. Even after switching the traction control off, I found it tough to get that tail to come out like it would on a BMW Z4 or Nissan 370Z. Some people will dig this fail-safe approach, but to me it seems at odds with the herd of horses cooped up behind that gloss-black radiator grille.

I could maybe excuse this in the now defunct TTS I drove a few years ago but in an RS, a badge reserved for only the sharpest Audis, the lack of dynamic appeal was actually rather disappointing.

Consequently, the only time the TT-RS really gets you buzzing is when you make full use of that wonderful turbocharged engine for bouts of face-warping acceleration. Other than that there's little in it that would entice me away from the slightly more expensive BMW Z4 sDrive35is or the perfectly balanced Porsche Boxster Spyder: cars that both offer much more reward when the road starts to wind. It's not that the TT-RS is a bad car; far from it. But in this company it comes across as being perhaps too one-dimensional.

A pity because with such trouser-tightening styling cues - that fixed rear wing and R8-esque body kit drawing more attention than a Playboy centre-spread - the Audi TT-RS could have been a true drop-top hero. Instead it teeters on the brink - a capable sports car that sure has the muscle but is crying out for a little more focus.