Mercedes SL review: SL500 and SL350

The new Mercedes SL has that rare, immediate sense of being “right”. There’s no learning curve and no need to acclimatise; it simply clicks from the outset, as if the engineers have quietly congratulated themselves and moved on. It’s usefulness without fuss - and it ought to be, given the SL nameplate has been around for 60 years. Mercedes has had plenty of time to refine the formula.

Mercedes SL: lightweight structure and materials

The way this SL has been developed isn’t magic, but it is satisfyingly pragmatic - the sort of engineering that adds up to a better car rather than a better brochure. The underlying structure is now largely aluminium, trimming about 110 kg from the core framework compared with the previous SL.

Dig into the technical detail and it’s a mix of cold-cast aluminium bolt-on sections and a broad spread of aluminium alloys, chosen according to position, loading and purpose. Putting it all together can’t be straightforward. There’s even a touch of magnesium (behind the fuel tank and within the roof frame), while the only conventional high-strength steel is reserved for the A-pillars to provide roll-over protection if you ever manage to invert one.

Weight reduction, efficiency and emissions

That obsessive attention to removing fat pays off. Despite the newer car generally carrying more equipment, the 320 kW (435 bhp) V8 SL500 is 125 kg lighter overall than its predecessor, while the 228 kW (306 bhp) V6 SL350 manages an even bigger generational drop of 140 kg.

You don’t need advanced physics to see the upside. On the combined cycle, the SL500 returns 9.1 L/100 km (31.0 mpg) and emits 212 g/km of CO₂, while the SL350 delivers 6.8 L/100 km (41.5 mpg) and 159 g/km of CO₂. Shed mass and you can spend the benefit on pace or economy - whichever matters most. Either way, it’s hard to argue with the result.

Stop/start comes as standard (and on the SL500 it’s especially discreet), as does the 7-speed 7G-Tronic Plus automatic, calibrated with efficiency in mind.

Performance: fast without the drama

Don’t mistake the greener messaging for a lack of muscle. The SL500 hits 0–100 km/h (0–62 mph) in a confident 4.6 seconds, with the SL350 following at 5.9 seconds. Both are limited to 250 km/h (155 mph). In other words, neither could reasonably be described as slow.

Ride, handling and Active Body Control (ABC)

It’s also happy when the road gets twisty - although doing so will naturally dent those strong economy and emissions numbers. The new body’s stiffness gives the suspension a solid foundation, and the upshot is a level of ride comfort that’s genuinely unexpected, without the looseness you often associate with convertibles.

Standard suspension is semi-active with adjustable damping, but the cars we drove all had Mercedes’s full Active Body Control (ABC) system - and it’s seriously impressive. At a cruise it feels smooth and pliant; press on and it tightens up, staying composed and grippy.

It deals with bumps in a slightly digital, processed manner, and the electromechanical Direct Steer variable-ratio rack adds to that sensation, but at no point does it make you question the engineering direction. The overall package feels properly rounded.

In fact, the SL can catch you off guard. It’s so accomplished at effortless, long-legged wafting that the cornering speeds it will ultimately tolerate can come as a surprise. It keeps clinging on - resisting understeer right up to the limit of your nerve. Meanwhile, the 4.6-litre V8 beats away like an elephant’s heart: effortless torque, easy power, and a relaxed ability to reel in the horizon through the windscreen.

Roof, cabin and design details

The finer details reinforce that steady stream of small satisfactions. The folding roof tucks away in a clean 14 seconds and looks superb whether raised or stowed.

Inside, it’s roomy and laid-back for two, with useful storage throughout. Even the electrically operated draught deflector that rises from the rear deck has its mechanism hidden behind a set of sliders, leaving no exposed moving parts.

The one element that made me wince, albeit mildly, is the new headlamp design, which appears slightly… bulbous on a car whose surfacing elsewhere has such clearly defined muscle. Still, it’s a handsome thing overall - less overtly aggressive than an SLS, but with enough long-bonnet, short-tail proportion to give all the right big GT signals.

SL350 vs SL500, plus pricing

So yes: the SL500 is a delight, and it works brilliantly. Even so, there’s a lingering sense that the not-yet-driven SL350 may be the true sweet spot of the line-up. Historically it’s been the buyer favourite, previously accounting for 68 per cent of sales.

It’s also a further 100 kg lighter than the SL500 (1,685 kg versus 1,785 kg), still offers comfortably more than 300 bhp, and is capable of 40+ mpg. For almost any use that doesn’t involve trying to impress outside a bar, that will be ample.

An SL63 is also on the way with a 5.5-litre bi-turbo V8, but that’s a separate story.

At the time of writing, final UK pricing had yet to be confirmed, although an increase over the outgoing model seems likely - even if not a dramatic one. European prices have been set at €93,534 for the SL350 and €117,096 for the SL500, including 19 per cent VAT. It’s a substantial outlay, but the standard equipment is generous and the overall experience is unapologetically premium.

There’s a risk, with cars developed through relentless auditing and a grind of microscopic perfectionism, that the end product loses something - that it becomes dull, or that a committee-led process irons out any real vision. Most of us want at least a little passion in our cars.

The SL avoids that trap. It’s genuinely brilliant, but in a softly lit way. It’s a car that grows on you. There’s no constant fireworks display; instead it offers a calm, intelligent and rigorous interpretation of what a GT convertible should be. The key is not to confuse compromise with true breadth of ability.