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…