Lighter, sharper and better engineered than the car it replaces, this fourth-generation Mazda MX-5 does everything right.

It’s offered with a 1.5 or 2.0-litre petrol engine and what it lacks in outright power it more than makes up in agility and tactility.

This fourth generation design conforms to five key criteria that Mazda claim define the MX-5 - rear drive with a front-mid engine layout, 50/50 weight distribution and an eagerness to change direction, plus a low kerb weight and an affordable price.

All models get six-speed manual gearboxes.

The shape of the MX-5 hasn’t changed radically from generation to generation.

This one’s no exception, but there’s a bit more aggression about the detailing.

It’s fully 105mm shorter in overall length than the outgoing version, despite the wheelbase only being 15mm less.

It also stands 20mm lower and 10mm wider. Lower and wider is always good for a roadster’s stance.

In another clever touch, the seat cushions are supported on netting instead of the usual metal springs, allowing Mazda to reduce weight and seat the driver’s hip point closer to the road.

A lower driver then means the windscreen header rail can shift backwards, in this case by 70mm, which in turn means the hood is shorter and lighter, and also easier to package when folded.

See what we mean about that virtuous circle?

Weight is the enemy.

Excess weight in a car dulls its responses, makes it harder to turn, stop and accelerate, ensures that it drinks more fuel and puts greater stresses on virtually every moving part, parts which then have to be beefed up and made heavier to cope.

The Mazda MX-5 reverses that cycle, stripping weight off which in turn allows it to pare more weight back with other simple lightweight componentry.

It’s a brilliant piece of engineering.

It also goes to show that you can probably have more fun with 1.5 litres worth of MX-5 than you can with some supercars.

No, that’s not hyperbole.

Try it and you’ll see.

If you measure your cars in terms of smiles per mile, the MX-5 has to be right near the top of your shortlist.