What you’re looking at here are the new Porsche Cayman GT4 and Porsche Boxster Spyder. And they are resolutely, gloriously naturally aspirated with six ‘boxer’ cylinders.

This will of course by music to the ears of everyone who bemoaned the fact that lesser versions of the latest 718-generation Cayster come with 4-cylinder turbo engines – excellent motors though they actually are.

Come to think of it, the new engines will be music to everyone else’s ears as well, as they sear round to 8,000rpm.

The Cayman GT4 and Boxster Spyder are both powered by a 4.0-litre unit – based on the 3.0-litre turbo engine from the 911 Carrera – that produces 414bhp and 310lb/ft of torque.

That’s enough for a 0-62mph time of 4.4secs and a top speed beyond 186mph.

That horsepower figure is a big jump over the previous 3.8-litre Cayman GT4 and Boxster Spyder. Torque hasn’t changed, but the new cars’ larger capacity mean there’s more torque over more of the rev range.

If it matters, both cars are now kinder to the environment, thanks a massive – and massively heavy – exhaust gas filter.

Porsche’s GT department has done rather more than bolt in a new engine, though. A lot of time was spent in the wind tunnel finding more downforce, most it produced by a whopping rear diffuser made possible by a repackaged exhaust.

Porsche claims the GT4 produces 20% more downforce over the axle than the its predecessor – 12kg at 124mph. The Spyder, too, produces real downforce at the back, making it the first Boxster ever to do so. In both cases, the downforce comes without the penalty of increased drag.

As you’d expect, the chassis has been honed and tightened with suspension lowered by 30mm and a rejigged stability control system. There’s torque vectoring and a mechanical locking differential as well. The brakes have been beefed up to match – ceramic rotors are optional.

The effect of all that is that the new Cayman GT4 can lap the Nordschleife more than ten seconds faster than the old car.

This writer got the opportunity to drive the previous Cayman GT4 at Porsche’s Silverstone Experience Centre and it was epic in the extreme. There’s nothing revolutionary about the new one, but in typical Porsche style they have been through it with a fine-toothed comb to improve every single part of it to produce a driving experience that will probably verge on the transcendental.

The only remaining question is whether or not you should go for the tin-topped GT4 or the open-topped Spyder. The GT4 will likely be the more focused driving experience, but the Spyder gives you unhindered access to the 8,000rpm soundtrack. Tough choice.

Prices start at £75,348 – which is pretty much the least you’ll pay for a decent 981-gen GT4. So not only is it an amazing car, it’s a solid investment.

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By Graham King