You might have thought, as we did, that the world's most perfect, tidy, eminently usable folding soft top didn't need to be replaced by a power-operated folding hardtop. Particularly in a simple, elemental car like the Mazda MX-5 Miata, the inevitable added weight and complexity could dull its reflexes and blur its focus.

Don't worry.

After putting a quick thousand miles on a 2007 Mazda MX-5 Power Retractable Hardtop (PRHT), we think the company's estimate of a 20-30-percent take rate on this option is going to prove low. In fact, for any duty this side of actual competition, we're prepared to say that the power hardtop version is now absolutely the right Miata to get.

Why? Simple. When you want an open car, this one's just as good, and when you want a closed car, this one's vastly better. With the top buttoned up, the PRHT is as quiet, comfy and secure as any steel-roofed coupe. Convertible, indeed. A header latch, one button and about 12 seconds are all that separates the two very different configurations.

We might question that flexibility if it came at the expense of chuckability and poise in the corners — the real hallmarks of the Miata driving experience — but it doesn't. The new hardtop adds about 70 pounds to the curb weight of Mazda's little roadster. Yes, that's a lump of mass you'd pay good money to remove from a true sports car. But it just doesn't create any identifiable issues.

Handling the load
Tossing the new MX-5 around on a bumpy country lane, you might envision those extra pounds and think, yes, maybe the car is just the slightest bit softer and more tail-happy (the four electric motors and most of the folding mechanism lie aft of the car's midpoint). But we guarantee you wouldn't notice a difference if you didn't know to look for one.

The incremental weight also didn't show up while whipping the car around on our test track with the timing equipment watching. Acceleration, braking, slalom and skid pad results were all within reasonable production variation, compared to the last MX-5 we tested. One measure that did show a difference was interior sound levels. That soft top registered 77.0 decibels at 70 mph; the new PRHT, just 72.9. That's a big change, one we especially appreciated in the final hours of a freeway haul back to Los Angeles from the Monterey Historic Automobile Races.

A slight increase in rear spring rate, damping rates and front antiroll bar diameter are all the chassis adjustments the additional weight called for. Otherwise, the MX-5 PRHT is mechanically identical to the familiar MX-5 soft top. In fact, it is also little changed visually. Aside from the top itself, touches of chrome around the grille opening, on the door handles and the headlight bezels, plus a modish white lens for the CHMSL, are all the distinction the new car gets.

Top engineering
But the top is distinction enough, and it's a beaut. Brilliantly engineered by the German supplier Webasto (they also did the excellent new C70 top for Volvo), the MX-5's folding plastic-paneled roof breaks and collapses using geometry not too different from that of the car's original fabric top. The upper panel lies on top of the folded stack to give a finished appearance, once the double-hinged rear deck panel drops back in place. Remarkably, the stack nestles into the same area the soft top used, so this retracting hardtop does not impinge on trunk space or usability. Actually, though the spec is unchanged at 5.3 cubic feet, a slightly higher rear deck surface creates marginally more cargo volume than the soft top car has!

The retractable top is available on all three trim levels of Miata: Sport, Touring and Grand Touring. Although our fairly loaded Grand Touring example carried a lofty as-tested price of $29,600, the base price on a Miata Sport PRHT is just $24,350, making it the cheapest retractable hardtop on the market.

A Miata with a soft top is still $1,800 cheaper, but the optional removable hardtop costs an additional $1,500, which means the 2007 Mazda MX-5 PRHT offers portability and lots of engineering for a paltry $300. A bargain.

That's another reason why we conclude the Power Retractable Hardtop version is the Miata to get.