In fact, the company is so obsessive about secrecy that as we pulled up outside the gates of the Weissach development centre two months ago to meet the engineers responsible for the new Boxster, I was first instructed to sign a confidentiality agreement. This banned me from telling you a dicky bird about the Boxster until now. And one of the clauses on the form was a threat to sue me for 50,000 Euros for each piece of information that might accidentally leak out if I dared open my mouth in public. Well, now the embargo has passed, so with a lawyer on stand-by, here goes.

As you've probably guessed from looking at the early hand-out pictures, when you first clock the new Boxster in the sheet metal, the visual changes hardly punch you in the face. Only the headlights look obviously different; despite a passing resemblance to the units on the 997, they're unique to the Boxster and incorporate the indicators. However, almost everything you can see is changed from the old model. It really works too, with a more exclusive, expensive look thanks to those plumped-out arches, pinched waist and bigger wheels. Porsche likes to say it has given the new car some 'bones' to its body shape and I can see what it means; the old car sitting beside the latest Boxster in Weissach's inner courtyard now looks strangely blobby in comparison. The new car oozes stylistic confidence and has a sharper, slicker, more grown-up appearance.

It's not just the sheet metal that's new. The roofline has changed slightly because the roll- hoops behind the seats have grown taller, and it has moved back a few centimetres as well. The side-glass now has a squarer outline, giving better visibility with the roof up and creating a bigger door cut-out for easier access to the cabin.
Inside, the feel and texture of the materials are a couple of notches above those of the outgoing model. The cars we were shown were luxo-spec examples with full leather upholstery covering the facia, doors and seats, and the overall effect was superb. Standard finish will be a new 'soft-touch' synthetic material for the facia and door-tops but leather will be standard for the wheel rim, handbrake and gear-lever. The air vents get aluminium trim, a material that also pops up on the instrument panel and gearlever of the 'S'.

There is a choice of four different seats in the new Boxster - manual, electric, sports and special adaptive sports seats that have adjustable side bolsters. The seats are identical to those in the new 911 and offer terrific support - if you can fit in them (John Prescott won't be trading in any of his Jags for a new Boxster).

Mechanically, it's more evolution. Changes to the induction and exhaust systems lift output of the S's 3.2-litre flat-six from 260bhp and 228lb ft to 276bhp and 236lb ft. Useful rather than earth-shattering increases, enough to trim a couple of tenths off the 0-60 time.

After a brief look around the cars it's time to go out and explore the sweeping roads that criss-cross the Black Forest, just south of Porsche's Stuttgart base. The two cars available to drive are both 'S' spec cars, one with ceramic brakes and a six-speed manual, the other with steel discs and a Tiptronic gearbox (the Tiptronic 'box remains in production until a new DSG unit comes on stream late in 2005).
I bag the manual, ceramic disc Boxster S to start the drive route. Clambering in, the first thing that's apparent is how much better the driving position is. Details like the pedals
being mounted 10-15mm further into the bulkhead than before, and a steering wheel now adjustable for rake as well as reach, make a big difference. The steering wheel itself is also an improvement, being slightly smaller now (lighter, too, thanks to a magnesium rather than steel inner frame) and with a marginally fatter rim. It all gels superbly, especially with the new, tighter fitting sports seats in our test car, making the prospect of howling around the demanding test route a mouthwatering prospect.

Even the flat-six sounds subtly different when you fire it up. A deeper note than the outgoing car could muster percolates through to the cabin; it's not any louder but it is somehow more cultured and still unmistakably Porsche.

Over the first few kilometres any worries that the new, variable-rate steering rack might feel weird disappear. In fact, I'll confess to not being able to tell the difference between this and the old rack, but that's probably because during the first three-quarters of a turn the gearing remains the same as before, after which the higher gearing starts to kick in. The steering feels marginally heavier and disappointingly inert for a Porsche at cruising speeds but I reckon a lot of that's down to our car's optional 19in wheels, wrapped in 235/35 front and 265/35 rear Michelin Pilots.

No complaints about the grip those Michelins deliver, though. Even messing about for the photography I could barely raise a chirrup from the tyres. Even if you up the speed dramatically I doubt you'll edge into the Boxster's outer limits of grip on the public road. Fortunately there's still pleasure to be had on the way up to that point thanks to the way the car engages you in the driving process. The shorter-throw gearbox deserves a mention here, too - even more of a pleasure to use than the old one, encouraging you to swap ratios just for the hell of it.

Another surprise is how well the new PASM (Porsche Active Suspension Management) system works. At the risk of adding yet another acronym to the automotive lexicon, this one is worth the effort of remembering, although it must be said that there wasn't a conventionally suspended Boxster on hand to compare the PASM against. The system provides a more than acceptable ride at normal speeds before automatically switching over to a more sporting set-up as soon as it senses the driver pushing that bit harder.

Each damper has its own infinitely variable rate independent of that of any of the others; in other words, each individual wheel is damped according to the conditions beneath it at any given moment. The system helps control excessive roll and pitch during braking and acceleration, as well as offering a better ride. Alternatively, the driver can select the sports set-up manually, via a button on the centre console, though since PASM can do this automatically in milliseconds, you wonder why you'd bother to stretch out your finger.

As you'd expect, the standard drilled and vented brakes - 318mm diameter front, 299mm rear - on the Boxster S are fantastically powerful. Both the standard and the S versions use four-pot callipers, but those of the S are painted red to help differentiate it from the standard car. Porsche no longer uses the vacuum from the inlet manifold to power the brake servo, now employing a dedicated vacuum pump run off the end of the exhaust cam. It's not an entirely successful move in my view, because the servo assistance has also been increased by 18 per cent over the old model, resulting in a softness to the brake pedal that's at odds with the precision of the rest of the car.

For the first time on the Boxster you now have the option of carbon-ceramic discs that lop 20kg from the unsprung weight of the car. Despite reports of these discs cracking after extensive track use, I remain a fan of the technology; not only do they offer tremendous braking feel and a beautifully solid pedal, they offer an extra layer of wheel control, their light weight making the dampers' job that much easier. At ΂£5349, however, they're a costly option.

The revised, 276bhp engine is magnificent. Palpably more powerful, it purrs contentedly through the mid-range before howling up to the 7200rpm redline. And there's stonking torque low down, significantly ahead of the old unit's. Maybe I'm sticking my neck out here, but I reckon this is as close to perfection as you can get with a normally-aspirated engine. According to Porsche, the standard Boxster's motor is an even greater improvement over its predecessor, but we'll have to wait until a drive next month to find out.

There's a depth of talent here that will be sobering for other manufacturers, especially those trying to break into a roadster market upon which the Boxster has enjoyed a stranglehold since launch. If and when Porsche launches a coupe version of the Boxster, maybe next year, it will be a threat not only to rivals, but also to the 911 itself. When the original Boxster was launched eight years ago, a choice 911 had 281bhp and cost close to ΂£60,000; the new Boxster S has 276bhp, costs ΂£38,720, is just as quick and better handling.

An engineer made a very telling remark just before I left Weissach: 'We had the money to do the Boxster properly this time around.' Certainly the new one makes the original feel old and clunky, which comes as a big surprise. When the Boxster S is this good, it makes you wonder if the 911's days are finally numbered after all.