Mercedes CLK63 AMG

As is often the case with AMG cars, the CLK63 is dominated by its engine. And what a unit it is! Gutsy, responsive and powerful, it has amazing performance and a bellowing soundtrack. Yet the rest of the driving experience suffers in comparison, and the CLK doesn’t feel special enough to justify the price. Arguably the coupé, which is £3,600 cheaper, would be a better bet.

The fight to build the world’s most powerful cars shows no sign of slowing – and it’s not only top-line German sports models and luxury machines which are benefiting. Smaller cars are feeling the heat, too.

While Audi has equipped the sizzling new A4-based RS4 Cabrio­let with a 414bhp 4.2-litre V8 unit, Mercedes has managed to squeeze an engine that’s a whole two litres bigger under the bonnet of its CLK Convertible.

And the results are staggering. The CLK63 badge is slightly misleading – the engine’s capacity is actually 6.2 litres – but that’s no drawback when you consider what’s on offer. Developing 481bhp and 630Nm, power is up 31 per cent and torque 23 per cent on the 5.5-litre V8 machine that it replaces.

Performance is best described as mind-bending. Use full throttle and your brain will have a hard time keeping pace as the CLK Convertible hurtles from 0-60mph in only 4.7 seconds. It could be even quicker, but the rear wheels struggle to get all the power cleanly on to the road.

Acceleration is accompanied by a savage bark from the V8 which sounds even better with the fully automatic soft-top lowered. Gearchanges are dealt with in the blink of an eye thanks to the specially adapted 7G-Tronic transmission, which suits this car very well. However, the rest of the driving experience pales somewhat in comparison. AMG is an engine specialist, and while the uprated chassis and suspension cope sufficiently, the im-provements don’t make this a particularly memorable machine.

It features composite brakes, new sports suspension and lightweight alloy wheels, but neither the stoppers nor the steering provides enough feedback, and you simply don’t feel particularly involved in proceedings.

That’s exacerbated in the drop-top due to its slightly less rigid structure. Nor are onlookers treated to a visual feast. Aside from more aggressively styled sills and bumpers, the CLK is rather understated for a car of this type. The subtle cabin modifications amount to little more than a set of chunky sports seats and a thick-rimmed steering wheel with paddleshift.

However, as a result of this muted approach, you’re unlikely to attract unwanted attention, and any passengers will be even more taken aback when you do hit the throttle.

That noted, £68,815 is an enormous amount to pay for a CLK, putting it in the firing line of Porsche’s 911 and Jaguar’s new XKR.