Let's get straight to the point; Mercedes's new SL is one of those cars that immediately feels right. Nothing to assimilate, or acclimatise to, simply an immediacy that speaks of engineers looking pleased with themselves and a hell of a lot of boxes ticked. The art of the unobtrusively useful. Mind you, it should be pretty well honed by now - the SL is 60 years old. Merc's had some time to get the recipe right.
The mechanisms by which the SL has evolved aren't exactly witchcraft, but have that pleasingly practical feeling that means they'll add up to something positive. So, the structure is now pretty much all-aluminium, saving roughly 110kg over the basic bones of the old SL. Poring over the technical specs, there's everything from cold-cast aluminium bolt-in bits to extensive use of aluminium alloys, depending on location, load and function. Welding the damn thing together must be a nightmare. There's even a hint of magnesium (behind the fuel tank and in the roof frame); the only traditional high-strength steel components are inthe A-pillars for roll-over protection, should you manage to flip it.
Rigorous attention to fat-free detail pays dividends. Even though there's generally more kit, the 435bhp, V8 SL500 is 125kg lighter than the previous version all-up, and the 306bhp, V6 SL350 goes some way better by managing a generational weight loss of 140kg. You don't need to be a physics professor to work out the advantages: the SL500 will produce an entirely respectable (for this amount of performance) 31.0mpg and 212g/km of CO2 on the combined cycle, and the SL350 an impressive 41.5mpg and 159g/km of CO2. Decrease the weight, and you can have more performance in terms of speed or efficiency, depending on which takes priority. Everybody wins.
Obviously, standard stop/start helps (a particularly unobtrusive system on the 500), as does a standard-fit 7spd 7G-Tronic Plus auto gearbox optimised for environmental benevolence. But don't let the eco flag-waving distract you; the SL500 will stamp its way to 62mph from rest in an authoritative 4.6secs, with the SL350 not all that far behind at 5.9. Both top out at the regulation 155mph. So, not slow, by any means.
It can do wiggly bits in between, too, though the impressive economy and emissions figures take a battering in the process. That very rigid new structure gives the suspension a decent platform to push from, meaning that although the car rides with a plushness that's genuinely surprising, it suffers none of the slop usually associated with convertibles. Standard suspension is semi-active and features adjustable damping, but the cars we drove were all equipped with Mercedes's full-house ABC (Active Body Control) - and it's very, very good. Sweet and supple when cruising, taut and clingy when you go faster. It smothers bumps in a slightly digital way, and the electromechanical Direct Steer variable-ratio steering rack doesn't help the feeling, but generally there's no point at which you wonder what the engineers were thinking; this is one rounded car.
In fact, the SL is a big surprise - so capable of the glide that when you realise how far you can push the cornering speeds, you get mightily impressed. It just hangs on and on - fighting understeer until the very end of your bravery. Of course, the 4.6-litre V8 thumps away like an elephant heart, all easy power and low urge, winding the horizon back through the windscreen with a kind of idle nonchalance.
And the detail backs up the little surprise-and-delight journey you travel with the SL. The roof stows in a slick 14secs and looks fabulous up or down. The ergonomics are relaxed and spacious for two, with plenty of storage. Even the electric draught-excluder that pops up out of the rear deck has a mechanism sheathed in a set of sliders so that there are no exposed working parts. In fact, the only thing that really made me squirm even slightly is the design of the new headlights, which look slightly... bulbous in a car with such distinct musculature running through the rest of the surfacing. But it's a cool-looking thing - not as aggressive as the SLS, but with enough long-bonnet, short-bottom to give off all the right big GT cues.
So the SL500 is lovely. And works really well. But, saying that, I have a sneaking suspicion that the as-yet-undriven SL350 might be the real-life sweet-spot in the range - and traditionally it's been the SL of choice and has previously accounted for 68 per cent of sales. It's exactly 100kg lighter again than the SL500 (1,685kg plays 1,785), comes equipped with over 300bhp and is capable of 40+mpg. Which will be more than enough in pretty much all cases that don't include showing off at the bar. There'll also be an SL63 with a 5.5-litre bi-turbo V8, but that's another story.
At the time of going to press, final UK pricing was still to be confirmed, but expect a rise over the price of the last generation, if not a huge leap. Prices have been confirmed for Europe at €93,534 for the SL350 and €117,096 for the SL500, inclusive of 19 per cent VAT. It sounds a lot, but the standard kit list is long and the experience defiantly premium.
Sometimes, swimming through a sea of such an insistent detail audit, such grinding attention to micro-perfection, makes a car into something less than it should be. Dull. It's very hard to have a striking overall vision when the view is held in committee. And we all like a bit of passion in our cars. But the SL isn't like that. It's quite, quite brilliant, but softly lit. It's a grower. There's not a great deal of shock and awe about anything it does, just a quiet, thoughtful, rigorous take on what a GT convertible should really be about. The difference being that we shouldn't ever mistake compromise for genuine breadth of ability.