I’ve always harboured a dream of owning another soft top. I’m not worried about the security of a fabric roof – I don’t care if the a cabriolet is more noisy.

So the M4 convertible will prove the answer for many people because it has a folding roof. It drops in about 20 seconds, eating into a rather large slice of boot space.

The roof is so good that I’ve almost forgotten I can enjoy open air motoring. Except for one thing, the M4 convertible doesn’t look half as pretty as it’s coupe sibling, seen in the photo.

There’s something about the back of the roof that doesn’t quite work aesthetically. The BMW is all sharp lines and aggressive bumps. The gentle curve of the folding roof spoils the profile of an otherwise terrific car.

I love driving the M4 but I simply wouldn’t but the drop top because a £60,000 open car should also be a beautiful thing, not a compromise.

With summer coming to an end, I’m off to Italy for a week to ride a Harley-Davidson on a grand tour. We’re back September 25 with another weekly car test…

There’s been plenty written about how this latest M3/M4 doesn’t have the same aura as the old version. It’s all to do with BMW dumping their 4.4-litre V8 and replacing it with a turbo 3.0-litre for improved efficiency.

Nothing beats the roar of a V8 but don’t be fooled into thinking our M4 doesn’t boast a rumble from those four tailpipes. It’s not quite a V8 gurgle – but it’s also a pure sound that hasn’t been manufactured by a man with  laptop, a la Jaguar F-Type.

So when I fired up the BMW this morning, the soundtrack was inspiring. It’s really just a taster of what is to come when the revs pick up – it lures you onto the open road where you can cut loose and enjoy yourself.

The downside? Well, those meaty tyres produce an awful lot of road noise in the convertible. I can only imagine that it is the same in the coupe. The constant hum changes pitch when you drive over different surfaces but it’s always there, forcing the Harmon Kardon hi-fi even louder…

I wasn’t sure BMW had delivered the right car when the M4 rumbled up the driveway earlier today. So good is the design of the convertible that it’s difficult to tell it apart from the M4 coupe.

Slip the open top M4 on a set of scales though and it weighs in almost 180kg heavier – mostly thanks to a complicated roof folding mechanism that is jaw-dropping to behold.

And there’s not doubt that first impressions of this brute of a sports car suggest all that extra weight does have an impact on handling – especially over rough surfaces at speed.

It’s astoundingly quick in a straight line but there’s definitely some flexibility in the chassis. This is still a fantastic car to drive but there’s also a price to be paid for choosing the open top option…