Next-gen roadster snapped undergoing cold weather testing with limo-derived cabin, soft-top roof and a telltale pair of V8-backed quad exhaust tips.
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The next-generation 2021 Mercedes-Benz SL has been spied testing on the snowy roads of Sweden, as new reports out of Europe suggest the new model will offer four-cylinder and V8 hybrid power.

The pair of prototypes snapped by our spy photography partners wear less camouflage than SL prototypes spotted in recent months (and photographed in Mercedes-Benz's own teaser images), but still leave most of the roadster's main styling cues hidden under plastic cladding and a swirly wrap.

Up front, LED headlights inspired by the latest S-Class flank an interpretation of Mercedes-AMG's Panamericana grille and a pair of lower air intakes similar in design to the performance arm's latest models – confirming we're looking at a high-performance version of the new SL.

Headlining the changes along the side is the inclusion of a folding soft-top roof – rather than the hard-top employed by its predecessor – while at the rear a pair of slim LED tail-lights feature.

Above: 2021 Mercedes-Benz SL 63 prototype, evident by its four-sided quad exhausts.

Also visible from the rear is our biggest clue at what's sitting under the bonnet: a set of four 'square' exhaust tips, typically associated with Mercedes-AMG's V8-powered models, from the C63 S to the E63 S – more on that in a moment.

20-inch alloy wheels fill the arches, wrapped at the rear in 295/35 profile Michelin winter tyres – around a 10 per cent increase in tyre diameter over the outgoing model, with wheel sizes up to 21 or 22 inches likely to be supported by the new rubber.

This round of spy photos provides our first glimpse at the new SL's cabin which, to the surprise of few, borrows heavily from the full-size S-Class limousine, with a 12.8-inch tablet-style infotaiment touchscreen and a freestanding 12.3-inch digital instrument cluster.

Above: 2021 Mercedes-Benz SL interior spy photo.

2021 Mercedes-Benz SL and Mercedes-AMG GT to offer hybrid four-cylinder and V8 engines, according to reports

The UK's Car magazine (February 2021 print edition) reports five powertrain options will be offered with the new Mercedes-Benz SL – and the next-generation Mercedes-AMG GT, with which the SL will share its platform – pairing either a four-cylinder or V8 engine with hybrid assistance.

Opening the range will be a trio of four-cylinders, led at the lower end by the SL 43 (and GT 43), pairing a 291kW version of Mercedes-Benz's 2.0-litre 'M254' turbocharged four-cylinder petrol engine with a 48-volt mild-hybrid system adding around 15kW.

Interestingly, the M254 is understood to be mass-produced – a first for the AMG GT range, given all engines currently offered with the coupe model are hand-built by AMG's engineers in Affalterbach. The entry-level 43 will also be the only rear-wheel-drive model in either line-up, with all other models powering all four wheels.

Above: 2021 Mercedes-Benz SL four-cylinder prototype (left) alongside a V8-powered SL 63 test car (right).

The SL 53 4Matic will reportedly upgrade to a 336kW version of the Mercedes-AMG A45 S hot hatch's 2.0-litre turbo-four, mated to 30kW of electric boost for a total power output "approaching 373kW".

Sitting atop the four-pot range is said to be the SL 53e '4Matic+' – an option reportedly exclusive to the SL – mating the SL 53's 2.0-litre engine with a 112kW rear axle-mounted electric motor for a total of around 447kW.

Unlike the upcoming C63 S sports sedan, a V8 option will be offered in the new Mercedes-Benz SL and Mercedes-AMG GT – two, in fact.

A 4.0-litre twin-turbocharged V8 paired to a 15kW 48-volt integrated starter-generator unit in the SL 63 (or GT 63) will, according to Car, serve as the entry point to the bent-eight range, developing 470kW for a 3.5-second 0-100km/h sprint time.

Sitting atop the range will reportedly be the SL 73 4Matic+, mating the 63's turbo V8 to a 150kW rear electric motor and a 30kW-capable 48-volt mild-hybrid system for a total of around 615kW.

The 2021 Mercedes-Benz SL is expected to be unveiled in full sometime this year, ahead of a likely Australian introduction in 2022.

Stay tuned to CarAdvice for more details on the new SL as its launch approaches.