Porsche places its Cayman GT4 and Spyder on the same performance pedestal
Twin peaks The Porsche Cayman GT4 clocks a Nurburgring lap time of 7min 28sec. PHOTO: PORSCHE

The range-topping versions of Porsche's mid-engined twins - the 718 Cayman and Boxster - are now faster and more desirable.

Visually, the bewinged Cayman GT4 is still the purposeful, no-nonsense option, while the Spyder is the head-turner. With a lower windscreen and distinctive flying-buttress soft-top extension stretching over its rear haunches, it is by far the best-looking Boxster.

But it is no longer softer than the GT4. Unlike its predecessor, it now has the same Porsche Motorsport-honed chassis and set-up as, and identical output to, the GT4. The previous Spyder shared the GT4's engine but had its output dialled down by 10bhp. The Spyder is now a topless GT4.

And that mid-mounted engine is a new 4-litre flat-six, in place of the previous 3.8-litre. It remains non-turbocharged, to preserve its purist proposition. It revs to 8,000rpm - some way shy of the 9,000rpm the GT3's similarly sized (but entirely different) engine hits, but still 200rpm beyond the previous GT4/Spyder's redline.

The result? 414bhp at 7,600rpm - an increase of 35bhp over the first-generation GT4 and 45bhp over the previous Spyder. Peak torque remains at 420Nm.

The transmission is as before - a six-speed manual with a wonderfully positive, short-throw shift and automatic rev-matching function on downshifts, although a dual-clutch version is in the wings.

Despite the extra power, acceleration to 100kmh is unchanged from the 4.4 seconds of the previous GT4. But at 13.8 seconds to 200kmh, the new duo are 0.7 seconds quicker than the old GT4. Top speed also crosses 300kmh for the first time - the Spyder hitting 301kmh and the GT4, 304kmh.

This time around, Porsche has paid close attention to underbody aerodynamics. There are undertrays and panelling front to rear to hone the airflow, culminating in a large, fully functional rear diffuser which generates immense downforce without adding drag. Combined with a larger rear wing and details like a more jutting front splitter, air curtains and a Gurney flap integrated into the front air intakes, the GT4 has 50 per cent more total downforce than before.

Elsewhere, the recipe for the cars remains largely unchanged. The front chassis hardware is straight off the 991 GT3's, a 30mm-lower ride height over the standard 718, adaptive Bilstein dampers, much larger brakes (also taken off the GT3) and reduced sound insulation for weight reduction.

Also, in the interests of weight loss, the Spyder's softtop is manually operated. Both cars weigh 1,420kg.

While spring and damper rates remain unchanged from the previous GT4, chassis software has been tweaked, with retuned electronic damper control, stability control and rear differential management.

All this, coupled with Michelin PilotSport Cup2 tyres using a bespoke compound (said to be 2 per cent grippier than before), allows the new GT4 to shave a full 12 seconds off the old car's Nurburgring lap time. At 7min 28sec, the new GT4 is also four seconds quicker than Porsche's own Carrera GT supercar of 2004. Porsche does not quote a lap time for the Spyder, but an engineer says it is "just a few seconds" behind its hardtop twin.

I drove both the GT4 and Spyder on road and the GT4 on track (at the thrilling Knockhill circuit near Edinburgh) and, in every setting, the cars felt devastatingly capable yet deliciously involving.

The ride is, as before, very firm, but in a controlled, nuggety way. Appropriate to the cars' raw, unfiltered ethos, there is more sensitivity to camber and surface imperfections than on other 718s, but thanks to resolute damper control, bumps and undulations are shrugged off with nonchalance.

The engine has a gritty, serrated note that goes into a deeper bellow at 4,000rpm. It lacks the top-end wail of the GT3 engine, but taking this powerplant to its redline is hair-raising nevertheless. The clutch is slightly lighter than before, but the gear ratios are too tall - even at very high speeds on B-roads, the car rarely gets out of third gear.

After the numb, artificially weighted helms of most modern cars, the steering on these Porsches is a revelation, the thin Alcantara rim chattering and writhing lightly in your palms, every swivel of the wheel resulting in an instantaneous direction change from the front end. There is no mode button to configure steering resistance. Porsche has chosen the perfect weight - meaty enough but not so heavy as to rob the steering of its delicacy.

Pushed to and beyond its limit on the track, the car holds no nasty surprises. It corners flatly, whips into and around bends feeling completely planted, and remains predictable and progressive even past its immense grip limits. The brakes are easy to modulate and have ferocious bite, refusing to wilt despite lap after flat-out lap.

The duo may be Porsche's entry-level GT models, but in terms of driver involvement and sheer grin-factor, they punch far above their weight. Porsche Motorsport has created another masterpiece. Or two of them, to be precise.