Hiroshima, Munich. Munich, Hiroshima?

Despite the manifest unfairness of comparing two cars drawn from different price segments, we thought that the mid-range BMW Z4 would disclose any weaknesses when placed against the legendary Mazda MX-5. Meanwhile, the Mazda would do what so many reviewers have claimed it does best – namely, punch above its weight. The quest: to find a classically proportioned two-seater roadster for fun and games on twisty lanes this summer.

Before we begin, it’s wise to reflect on what you don’t get with these cars. You don’t get a meaningful trunk, you don’t get four seats and you don’t even get much in the way of bragging rights on today’s status-obsessed highways. Even if you commute to work with only a briefcase for company, the cars featured here are low to the ground and slightly awkward to get in and out of. They may not accommodate a large box of files, and they certainly won’t accommodate two suitcases.

All this makes the test drive quite simple, however. If you’re in this marketplace, you’ll only be wanting a car for its driving performance, its looks and its collapsible roof.

That makes the Mazda the winner in the roof stakes, because a collapsible hard top that retracts in just 12 seconds is a work of genius. Period. Meanwhile, we actually preferred the gloss black dash of the Mazda, accented by optional black leather, to the slightly gaudy taupe, beige and aluminium circus of the Z4. It’s as if the Japanese were trying to be German while the Germans were trying to be Japanese, all backdated a decade.

On the outside, the two cars are worlds apart. With the Mazda you get classic curves, while the Z4 dishes up sharp, crisp, futuristic lines with clever cues such as the BMW blue and white propeller masking a side indicator.

Women seem to love both cars, so there is no discernable split even in terms of gender. Only the innate aggression of the BMW brand might turn potential owners on or off.

But jump in and turn the key, and there is no doubt which vehicle you’re driving. Unless you’re completely blind to dynamics and performance, and unless you shudder at the judder created by the blindingly stiff Bimmer chassis, you’ll step out wanting Munich rather than Hiroshima.

First off there’s the drivetrain issue. Despite ceding little on paper to the BMW in terms of acceleration or top speed, the Mazda feels slower, no doubt because the BMW punts along like a leaf in a gale, powered by its larger-displacement, six-cylinder engine.

More importantly, the German car sounds brilliant – surely a major plus when remembering the importance of aural elements in a drophead coupe.

Imagine you’re driving along lanes with rocks or dry stone walls at the verge. You want to savour the engine note, the exhaust, the sheer sound of driving.

Unfortunately the Mazda is uninspiring in this department despite its beefier-than-normal exhaust tone and gruff, mostly likeable engine. It’s a lovely, sweet unit, but it never succeeds in sounding like anything more than a Japanese sewing machine sprinkled with steroids. The more you rev it, the coarser it gets.

The reverse is the case with the BMW, which serves up a classic straight six that zings as you wring it out. The BMW also has perfect ergonomics, its gear lever falling straight to the hand and offering up a beautifully short throw action.