THE Mercedes-Benz SLK has always had its allure, but the third generation moves it to a new level.

Two-door sportscars with folding metal (or metal and glass) roofs are archetypal niche vehicles.

Regardless of its deficiencies, the original SLK wooed many customers with gorgeous looks and convertibility fronted by the three-pointed star, but it was no serious rival for the Porsche Boxster (fabric roof notwithstanding).

The second generation (R171) did a better job of matching sports handling and performance with the styling but to many eyes it was too soft and ‘feminine’ (whatever that means!).

This brand-new SLK represents a tour d’force. On some other models the incorporation of cues from the great Mercedes-Benz tradition seem forced, one example being the rear guards on the E-class said to reference the ‘50s ‘Ponton’ ancestors.

But the SLK evokes the beautiful 230SL of 1963 as well as the 190SL and Gullwing of the 1950s, while looking absolutely contemporary.

The design is so utterly resolved, the nostalgic elements so beautifully rewritten into a 21st century narrative, that you half expect the driving experience to be a disappointment.

Well, it isn’t – provided you remember to engage the sports mode.

At first blush a 135kW 1.8-litre turbocharged four-cylinder engine seems wrong for this application.

But we suspect very few customers will be disappointed when they experience the strong acceleration and mostly effortless torque.

Zero to 100 takes just seven seconds, which is better than respectable though not the stuff of supercars. The combined fuel economy figure of 6.9L/100km is excellent.

There are two important ingredients at work here to extract the most from the modest muscle beneath that sublime bonnet.

The first of these is the ‘low-blow’ turbocharger which favours driveability over high-end power.

The peak torque figure of 270Nm is admittedly modest but it arrives at just 1800rpm and remains on tap right through to 4600rpm. Many naturally aspirated four-cylinder engines of 1.8 litres develop maximum torque at considerably beyond the 3000rpm mark.

The second is Daimler’s superb 7G-Tronic Plus automatic transmission. Having seven gearbox ratios instead of, say, five gives easier access to whatever reserves of power and torque the engine has on offer.

Think of it this way: the 135kW of power and 270Nm of torque would probably equate to 160 and 320 respectively, if the transmission were a five-speeder.

In real-world driving, the SLK200 never feels underpowered. With the arrival of the premium 7G-Tronic Plus, manual gearboxes have slipped quietly off the agenda for Australia.

As with some other current Mercedes models, the Sport mode should really be the default setting.

It adds extra heft and quickness to the steering without ruining the ride quality, which is supple though firm.

The first-generation SLK displayed a disconcerting degree of ‘scuttle shake’ but this car feels very stiff and integrated, although perhaps not to quite the degree achieved by the latest BMW 6 Series Convertible.

With the metal roof erected, of course, there is no hint of body flex – despite the fact aluminium is now used for the bonnet and doors. The coefficient t of drag is a remarkable 0.30 (down from 0.32 on the previous SLK).

The interior, too, is better executed than any other Mercedes we can think of.

For nearly 20 years Mercedes’ interior design has rarely matched BMW, let alone Audi. But the SLK’s is consistent with the model’s exterior beauty.

There’s none of that cluttered, overworked feeling you get in, say, the CL coupe range.

Genuine brushed aluminium graces the fascia, reinforcing the marque’s glorious sporting heritage. The SLK is a supremely indulgent car for two and it really is difficult to believe that Mercedes-Benz Australia can bring such an appealing convertible to market for $83K.

Furthermore, there is no hint of skimping on the specification so that, while the entry-level SLK cannot match the six-cylinder 350 variant ($118,900), it is by no means disgraced in the comparison.

As with any Mercedes (or BMW or Audi), reckless ticking of the options boxes quickly adds many thousands to the pricetag. Even metallic paint carries an impost of $2080.

Even though silver (Iridium in this case) is the natural choice for a Mercedes-Benz roadster, we’d settle for solid white and put the money towards the $5900 AMG Sports Package judiciously specified by the public relations team for the test vehicle.

It turns an already highly appealing vehicle into a seductive one.

Eighteen-inch alloys replace the standard 17s and sports suspension is fitted. You get a more stylish steering wheel trimmed in Nappa leather and accommodating paddle shifts, and there are numerous lovely details such as red stitching on the black leather seats (other colours are available but not necessarily with the red stitching) and LED driving lights.

It’s an integrated options package that brings out the best of the already captivating SLK. If you’d somehow escaped all knowledge of this option and bought a stock-standard entry-level SLK200, we reckon you’d curse yourself when you discovered what you missed.

There are also three versions of the standard folding hard-top roof. The SLK200 comes with a body-coloured version. T

he next two are glass, with the premium ‘Magic Sky Control’ changing colour from dark to light at the press of a button. You’ll pay $3182 for that privilege.

You cannot lower the roof unless a removable panel is in place over the lower section of the boot (to protect luggage and, indeed, the roof) and there is a particularly neat little reversible panel that changes the shape of the boot well when the roof is erected.

We cannot comment on the standard car’s agility and the driving pleasure it yields, but the SLK200 with AMG Sports Package is an unmitigated joy with Sport mode engaged.

‘Roadster’ is a term whose meaning has shifted with the years but it has always had connotations of a driver’s car and this latest SLK will have you thinking of Moss and Jenkinson in their 300 SLR on the Mille Miglia.

The only sensory ingredient missing from this experience is an evocative exhaust note, although the AMG pack’s ‘sports engine sound’ helps. That throttle-blipping sound under full acceleration is welcome but hardly compensates for the humdrum note the rest of the time.

While the new SLK does not have the uncouth, raucous sound of the first-generation car, its music does not match its looks. But would you really care to pay $118,900 for the six-cylinder SLK350? Just turn up the Beethoven…

In summary, the new SLK is among the best cars we have tested this year. Even the entry-level version delivers strong performance and if you specify it with the carefully tailored AMG Sports Pack you’ll have a bespoke Mercedes convertible that richly evokes the marque’s long sporting tradition.