Mercedes doesn't tinker with the SL too often and the launch of an all-new car is something of an event.

Future-proofing a car in such a fast-moving development environment will prove tough but there can be few complaints as to the engineering on show. It would be tempting to think that a car in this class doesn't have to be that good to drive. This is Mercedes though and the depth of engineering verges on the neurotic.

Engines? Tick that box. A new 4.7-litre V8 in the SL 500 develops 430bhp, up around 12 per cent on its predecessor while offering 22 per cent better economy. It's significantly faster than the old SL500 as well, carving almost a second off that car's sprint to 60mph, in this instance stopping the watch at just 4.3 seconds. Don't be foxed by the 3499cc capacity of the V6 either. It might appear to be the same as the V6 in the old SL but this is also a new motor. In the SL 350 it makes 303bhp and this translates to acceleration to 60mph in just 5.6 seconds.

The biggest bang for their buck that car manufacturers can get is by taking unnecessary weight out of cars and old-school two-seat roadsters have often been notoriously lardy. The SL had grown a bit like that, which was a shame as the original model of 1952 featured a featherlight lightweight tubular frame. This time round, Mercedes has put the SL on a weight loss plan with its first all-aluminium bodyshell in a series-production model.

Only very few components consist of other materials. The designers use the even lighter magnesium for the cover behind the tank. High-strength steel tubing is integrated in the A-pillars for safety reasons.

The new aluminium bodyshell weighs around 110 kilograms less than it would using the steel technology from the predecessor. Those traditionally sold on the charms of a Mercedes SL will certainly be sold on this one. They'll certainly like the look of it thanks to the lithe proportions and deft detailing. It'll be fascinating to see how this model will develop.

There will undoubtedly be a prodigiously powerful AMG version in the offing but we keep hearing rumours of a diesel SL being added. That would certainly cover off what BMW has done with its successful diesel 6 Series drop top and shouldn't be an insuperable engineering issue for Mercedes.

Whatever happens, expect this SL story to be compelling.