Just as Porsche's Cayman is so much more than a Boxster with a roof, so the Z4 M Coupe is a whole lot more than just a tin-top version of the Z4 roadster.
This is the hardcore M, the uncompromised driver's car in the Z range. To make that point perfectly clear, BMW brought us to Estoril, the former Portuguese F1 circuit where Jacques Villeneuve stuck a passing move on Michael Schumacher that we're still talking about today. It's tight in places, oh-my-god fast in others. And, as two journos found to their cost, it'll bite you on the bum if you get it wrong. Hard.
But first the car. Adding a steel roof (it's so small there'd be no point in doing a carbon-fibre one as on the M6 to save weight) has doubled the torsional rigidity of the Z. The result is a car that's Porsche 911 stiff - which is very stiff indeed.
Full review here