The SEMA motor show is good for fans of 900bhp Mustangs and curious bodyshop specials.

But this year’s show has yielded some less predictable concepts. Namely a couple of Mazda MX-5s that look even more delightful than standard. Meet, from left to right, the MX-5 Spyder and the MX-5 Speedster.

We’ll start with the Speedster, simply because it’s the one we’re more gagging to drive. It slices nearly 200 kilos from its base car’s kerb weight, tipping the scales at a mere 943kg thanks to its complete lack of roof.

The windscreen, you’ll note, is replaced by a dinky wind deflector, while the doors and seats are made of carbon.

Mazda describes it as “a study in the extremes of lightweight, purpose-built performance,” and the MX-5’s 158bhp 2-litre engine continues service. The ride height is 30mm lower, though, while there are smaller 16in alloy wheels, wrapped in very trackday-biased Kumho tyres.

With its skimpier kerb weight yielding a 168bhp/ton power-to-weight ratio - a 20 per cent improvement on standard - performance ought to be notably sharper. We’ve got our helmets and racing gloves at the ready, Mazda…

Those of a less track-biased disposition are likely to prefer the Spyder, meanwhile, which appears to have taken a leaf from the book of Porsche’s identically suffixed Boxster.

The traditional folding soft-top has been replaced by something Mazda rather teasingly calls a ‘bikini top’. Really.

It looks far faffier to deconstruct than standard, but much prettier to observe, while the interior is a less barren affair than the Speedster, with lots of lovely leather to “capture the character of a vintage roadster”.

The Spyder also uses Mazda’s 2.0 engine, and it comes with adjustable suspension and some rather sticky looking Yokohama tyres, too. It shares a carbon aero body kit with the Speedster, proving it’s little less focused. It’s 100 kilos heavier, but it’s fair to say it’s still a welterweight.

Two slightly different, conceptual takes on the MX-5, then, but we’d rather like to see both make production. But given Mazda didn’t follow through on its old Superlight concept, we shall remain cautious…