Porsche's soul is devoted to hardcore speed. Ride quality is an issue, but if the guys from Stuttgart have to sacrifice a bit of that for an extra 3mph through an apex, then given half a chance they'll do it.

Which is why the 911 Turbo hasn't gone down as well as it might have with Porsche devotees in its current guise. It's still a Porsche, so they don't dislike it exactly, but the fanfare hasn't been as great as with, say, the GT3.

This might sound improbable for a car with such crushing abilities by all reasonable standards, but the 911 Turbo is a bit soft and heavy in relation to even more focused 911s. As a result, the new Turbo Cabriolet is unlikely to be one of those iconic Porsches that fetch such silly money at auctions these days.

'A bit soft' does not mean slow. The 911 Turbo Cabriolet is still ludicrously fast.

Power delivery via the twin variable-geometry turbos is not exactly what you'd call smooth - accelerate from below 1,500rpm, and you wonder what all the fuss is about at first; 2,000rpm arrives without much fanfare, but you can begin to feel a bit of drama building; 3,000rpm is the warm-up act; then 4,000rpm arrives, and it's as if the Rolling Stones have suddenly set up a full-blown concert behind your head.

You can hear great dollops of air being sucked into the rear, and the car just launches itself up the road. Beware of poking the throttle pedal playfully mid-bend: you get a moment's delay as the turbos spool up, then you're hanging on.

If you spec one of these with the Sport Chrono Package Turbo option (1,015 of your finest pounds Sterling), then power is 480bhp, torque is 501lb ft and the horizon arrives extremely quickly indeed.

It's four seconds dead from 0-62mph in raw numbers, which means that you need to be driving a Lamborghini Murciélago LP640 Roadster to go much quicker without a roof. Or the Tiptronic S version of this car, which is faster to 62mph than the manual equivalent by 0.2 seconds.

The Sport Chrono option boosts torque by 44lb ft when you hit the Sport button, but to be honest I'd leave it off your spec list. It's simply too brutal - the turbos kick in with such a shove that you've got to be red-hot on the next up-change, otherwise you slam into the jarring rev-limiter. Only get it if you absolutely must have the fastest 911 Turbo. Oh, and if you fancy the lap timer that sits on the dash.

What 'a bit soft' does mean is that the Turbo Cab doesn't attack corners with the merciless rigidity of other 911s. The ride quality is very impressive on this car - even with the 19-inch wheels, it still rolls over small bumps better than many other sports cars.

This is helped by the ceramic brakes fitted to our car - they're 30mm bigger than the steel ones, but 50 per cent lighter, which reduces the unsprung weight. And interestingly, they don't squeak as much as ceramics originally used to.