For as long as I’ve been doing this job, high-performance Mercedes-Benzes have rarely reached the heights of rival products from BMW. But now, it seems, in one area at least, they may have sneaked past.

I actually drove the BMW M5 featured on page 118 and the Mercedes-Benz E63AMG back to back, and had planned to bring you a straightforward comparison of the two. But in the event the Mercedes was supplied on winter tyres and the BMW on standard rubber and the variances resulting in ride, refinement, steering feel, grip and handling progression would have skewed subjective judgement, one way or the other, in all these areas.

But I can tell you this: were it the old M5 meeting the E63 before it was given a new twin-turbo 5.5-litre engine, my strong instinct is that the BMW would win. Now and thanks in part to the M5’s changed priorities, the rejuvenated E63 is the one in which I’d prefer to spend more time.

On paper the performance,economy and emissions of the two are all but inseparable, but once on the road their two characters strike real contrasts. And it’s the Mercedes that is the more gruff, responsive and eager, and the BMW that is more comfortable, relaxed and urbane. In other words the E63 is more like an M5 than an M5.

sports saloons mercedes  Mercedes Benz E63 AMG

To begin with, it is the Mercedes that feels lighter (because it is, to the tune of over 100kg) and more nimble, but the thing that really makes the difference is what I believe to be the best turbocharged engine in the performance car world. The high-displacement, low-boost strategy that Mercedes has adopted appears to achieve the best of both worlds: normally aspirated throttle response and sound combined with turbo torque and fuel consumption.

What I really want to know is what this engine would do in a C-class, but apparently it doesn’t fit so we’ll have to wait for the next generation.

Engine: 5.5 litres, eight cylinders, twin turbocharged
Top Speed: 155mph (limited)
Price: £74,895
Power: 525bhp at 5250rpm
Fuel/co2: 28.5mpg, 232g/km