It’s not often a car manufacturer goes out of its way to lower expectations of a car before you drive it, but BMW did a good job with this new 3-series convertible.

Albin Dirndorfer, its project manager, claimed convertible drivers were more interested in a “relaxed” drive than a sporting one, and then went on to point out that the coupé on which it is based met “much higher dynamic requirements than the convertible”.

I was rather heartened by this. Indeed I applaud BMW for daring to say what other convertible manufacturers know but still absurdly try to cover up: namely that there is not now, nor has there ever been, a convertible that’s as good to drive as the closed car on which it’s based.

The reasons are always the same: convertibles are structurally less rigid than coupés and, in an attempt to ameliorate some of the worst symptoms of this lack of torsional rigidity, manufacturers reinforce the chassis, making the cars much heavier. In fact the convertible 3-series weighs 463lb more than the coupé.

To understand what effect that might have on its performance, handling and economy, imagine how your car might behave with two baby elephants on board. Exactly. In fact once you’ve added an average driver, the convertible is heavier than an empty 7-series limousine.

What’s remarkable, then, is how little this appears to have dented its performance: the top-of-the-range 335i model is just 0.3sec slower to 62mph, its top speed is the same electronically limited 155mph and its fuel consumption has fallen just 1.2mpg. This, however, is not how it appears on the road.

Despite the fact that convertibles usually feel quicker than they are thanks to their proximity to the elements, this 335i never felt like it had 306bhp under the bonnet. When I drove its coupé sister last year I described its performance as relentless. This one never graduated beyond pleasantly quick, and you can thank the elephants for that.

There's no question about it, the M3 is one of only a handful of cars on just about every enthusiast's dream list for the last twenty years or so. The reason for that is simple: It uses the BMW 3-series-the best sports sedan in the business-as a starting point, and trims the fat even farther.

Since the first M3 debuted in 1988, it has grown in just about every way, and the new M3 is no exception. It has twice the amount of cylinders as the first M3 and more than twice the horsepower. Luckily, it doesn't weigh twice as much weight.

That means this M3 will be the fastest one yet. We're still waiting for BMW to release final numbers, but under the hood resides a 4.0-liter V-8 that we expect to make about 415 horsepower. That's 115 more horses than the twin-turbo 335i, which is already almost as fast as the last generation M3.

It used to be that quick cars made 115 horsepower - not 115 more than other ridiculously fast cars. Here's to wretched excess! Sign us up.

The car you see in these photographs is being shown in Geneva as a concept, but expect the production car to look the same. Changes relative to the coupe include the power dome hood, unique front and rear fascias, rear diffusers, a carbon fiber roof, and the vented front plastic fenders. In fact, the only body parts the M3 shares with the standard 3-series coupe are the angel-eye headlights, taillights, doors, deck lid, and glass.

The nineteen-inch, sixteen-spoke forged alloy wheels should make it to production, and we expect they will be connected to the high-revving V-8 by way of either a conventional six-speed manual transmission or a new twin-clutch unit a la DSG. SMG is, thankfully, dead.

But the M3 is very much alive.