Even in a world familiar with the concept of downsizing, a 2.0-litre Mercedes SL seems really strange. As recently as 2019, an SL63 had a 5.5-litre, twin-turbo V8 in it, as the old R231 generation never adopted the 4.0-litre hot-v. There’s a 2017 SL65 in the classifieds complete with a 6.0-litre V12 in it. Life comes at you fast, so they say, and never more so than for AMG Mercedes Benzes.
Still, if there’s a four-cylinder engine to kick an SL range off with, there aren’t many better than AMG’s M139. Yep, here it is again, narrowly missing out on top spot to the Lotus Emira in the competition of ‘places you didn’t expect to see an A45 engine’. It’s a different version, too, mounted longitudinally in the SL and with the 382hp output offered in other markets as a non-S A45 hatch. This has the electrified turbo not seen elsewhere, with a starter generator helping out with a few horsepower and aiming to eliminate lag by spooling the ‘charger before the exhaust gases can. As is the modern AMG tradition, the SL43 is a complex performance car.
Notably, however, it goes without a good chunk of the kit seen in the V8 models, including the four-wheel drive and rear axle steering, officially saving 160kg over an SL55. So much of it will be over the front wheels, too, and the impact is immediately obvious. The spry, energetic agility that characterises the V8 has carried over intact, even with half the steering wheels - perhaps there’s something to be said for this small engined sports car thing.
Indeed, it doesn’t take long behind the wheel of the SL43 to wonder why AMG couldn’t have sorted all the old drop-top hot rods this well. Such is the urgency, precision and keenness of this platform that it soon gives the impression of a small, sporty SLK for the 2020s, banishing any lingering memories of lumbering Sport Leichts to the bin. Even sat back with a sizeable bonnet ahead, you soon have great confidence in the steering response, placing the big Benz between the hedgerows without a second thought. Fairly light weighting seems more appropriate for this slimline version than the full-fat V8s. It feels tight and taut in a way big Mercedes like this never have, but AMGs so often do, and that’s a good thing.
It's a shame there’s not more of an Affalterbach vibe to the engine. Inevitably some of that feel will come from the inescapable facts of physics - it’s 382hp and 354lb ft moving 1,800kg - so it’s never going to feel as feisty as a 421hp A45 or even a 360hp Emira. But also, as with the Lotus, there’s the impression that the full AMG experience is saved for the most potent version. Here the M139 doesn’t quite rev with the same reckless abandon, and while a reduction in lag from the electrified turbo is useful in terms of drivability, it does nothing for excitement. Neither do the apologetic exhaust pops of the sportier drive modes. The nine-speed auto can be indecisive, furthermore, changing down gears and holding onto them at unexpected moments. The aluminium paddles improve the situation, though you’ll search in vain for the thrill of a dual-clutch. Normally you’d not begrudge an SL that, but the slackness is notable in a car seemingly so sharp elsewhere.
So where the engine may once have been a centrepiece for an AMG SL, that’s not really the case for this SL. But then it was never intended to replace the V8s - it’s taking the place of the old V6s - and for that job it’s more than amply equipped. Fast enough, more than responsive enough, subdued at a cruise and not unpleasant to listen to. And, obvious though it may sounds, this ’43 definitely still looks like an R232 SL, and that’s a very good thing. The badge might be different and the wheels an inch smaller, but it remains a really arresting roadster. And that’d still be true if not in yellow. If buying a convertible is about making an impact and making yourself look good (be that at the golf club or elsewhere), then the SL - even the 2.0-litre one - nails that brief.
It's an inescapable fact: driving the ’43 was a more than enjoyable experience. There’s great stability and composure under braking and through bends, loads of grip to lean on (and just a little bit of feel through the seat to gauge it), enough performance to be fun and a firm, reassuring brake pedal. Just as with the more senior models, in fact. Trouble is the ’43 also does exactly what the V8s do and just starts to fray at the edges when the going gets tough. Which is such a shame given how encouragingly it begins, if boding well for the GT. There’ll be a slight shudder from the structure (or squeak from the dash), maybe a thump from a wheel, some unchecked movement that undermines your faith and cools your boots a tad. Up to a point the SL43 is really good, and its threshold can be found way beyond any previous comparable Mercedes sports car, but it feels worth drawing attention to. Experience suggests that perhaps a 911 would do even better on a similar road, but it would undoubtedly be a close run thing.
The SL43 offers up a very good account of itself in isolation; indeed it’s only when compared to those rivals (and with a spec sheet to hand) that the case begins to unravel somewhat. Because it’s a 2.0-litre car that costs £108,000. And however impressive this is as a Mercedes SL and an AMG product, that just doesn’t compute. The aforementioned Porsche cabrio range starts at similar money with a flat-six, and while cars like the Lexus LC and Jaguar F-Type can’t offer the same sort of aptitude, they’re both great looking drop-tops with stirring V8s for similar (or less) money. An M4 isn’t as pretty or as pure-bred, but it offers a heap more performance and practicality.
Which does make the SL43 somewhat of a tough sell. It can be heartily recommended to those sold on the new SL’s look inside and out, yes; a ’55 is 50 per cent more expensive again, and this does still drive well. But engines never matter more than when dealing with convertibles, and especially when spending six figures. The AMG 2.0-litre simply doesn’t sit quite as comfortably in the SL package as it does the A45 one. There are certainly some scenarios where a V8 remains the best option, if possible - make the most of them while you can.
SPECIFICATION | 2023 MERCEDES-AMG SL43
Engine: 1,991cc, four-cyl turbo, plus 48v ISG
Transmission: 9-speed auto, rear-wheel drive
Power (hp): 382@6,750rpm
Torque (lb ft): 354@3,000-5,000rpm
0-62mph: 4.9 seconds
Top speed: 171mph
Weight: 1,810kg
MPG: 31.1 (WLTP)
CO2: 207g/km (WLTP)
Price: £108,165
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