Mercedes-AMG is spearheading development of the next-generation R232-series SL convertible, which the go-fast division says will be lighter, sportier, and more practical. In 2018, two outlets reported two different scenarios with regards to the coming cabrio's engine lineup. Automobile claimed a four-engine range from 435-horsepower AMG SL 43 to an 805-hp AMG SL 73, and none of the three-digit designations typical of the Mercedes-Benz division. Autocar, conversely, figured on three standard Mercedes models from a 300-hp SL 300 to a 455-hp SL 500, on top of two AMG models: an SL 63 and SL 65. Now, a report on the Daimler-loving site MercedesFans.de (translated) credits an insider for a slide showing model designations for the new convertible, and the leaked info points more to Automobile's vision but with a few surprises.
The slide shows an SL 43 as the entry-level trim, the assumption being a 3.0-liter twin-turbo inline-six found elsewhere in the AMG lineup along with help from a 20-hp, 48-volt mild-hybrid system. That engine without the hybrid help currently produces 385 hp and 384 pound-feet of torque in the C 43 sedan. French magazine L'Automobile (translated) wonders if AMG won't instead turn to its bonkers 2.0-liter turbocharged four-cylinder for the 43 trims, especially seeing as the next AMG C 63 is supposed to get a four-pot hybrid. According to the slide, the entry-level SL would be the only rear-wheel-drive trim, the rest employing Mercedes' 4Matic AWD system.
Next up comes an SL 53 4Matic+, presumed to be the same 3.0-liter twin-turbo inline-six with EQ Boost as in the E 53, currently making 429 hp and 384 lb-ft. The next model name reads SL 55 S 4Matic+, which is a puzzler. It could be a touch of nostalgia from 12 years ago, with AMG also resurrecting the SL 73 moniker from 19 years ago. On the other hand, we've seen spelling errors on these types of early development screen shot leaks before, so we wouldn't be surprised if the model was actually an SL 53 S. Following that, a third 53 model is presumed with the SL 53e 4Matic, thought to get a 522-hp version of the brand's 4.0-liter twin-turbo V8 and a plug-in hybrid powertrain. This model doesn't come with the performance-enhanced 4Matic+ system, possibly because AMG engineers have developed the electric components to perform the same or better dynamic jobs.
Next comes an SL 63 4Matic, potentially carrying a 612-hp version of the 4.0-liter twin-turbo V8. Finally, the SL 73e 4MATIC, also omitting the performance AWD, and ready to crush everything in the segment with an 805-hp, 738-lb-ft powertrain derived from the AMG Project One, which will serve the AMG GT 73 as well. If the trademarks applications come true, that PHEV system could head to the coming S Class and a future G Class model, too.
The all-AMG model names on this highly speculative leak don't preclude the presence of standard Mercedes models, as in the Autocar report. However, adding standard versions would result in a ton of variants for what will be a low-volume product, at a time when Mercedes is paring back its lineup. On top of that, the cars Affalterbach has developed on its own — SLS, AMG GT and GT/4, and Project One — don't have Stuttgart equivalents.
There's firmer ground when discussing what will surround that engine. The aluminum-intensive MSA platform will shed up to 330 pounds compared to the current model, even as the R232 transforms into a 2+2 in order to separate it from the AMG GT. The switch from a retractable hardtop to a multi-layer soft top with its smaller storage footprint will allow more room for occupants and cargo. The 48-volt systems will power active stabilizer bars, the cabrio's dynamic capability additionally helped by a low, rearward engine placement and rear-wheel steering. And an AMG insider described the new body as a "butch, almost mean-looking sports car" with large intakes and plenty of vents, aggressive headlights, and integrated, horizontal taillights.