SPY PICS: New Mercedes SL in sheep's clothing

It takes little more than a second glance to see this Mercedes-Benz E-Class sedan snapped by spy photographers as it circulated Germany’s Nurburgring is a lot – a lot – more than it first appears to be.

In fact, speculation is rife that what looks to be an almost ridiculously-shortened E-Class sedan with a visible roll cage (and non-matching front and rear wheels) is actually an early test mule for the company’s next-gen SL-Class luxury sports car.

Clearly there’s something going on under the sheetmetal: In addition to the truncated body and rear doors (and wheelbase), the meaningfully pumped-out wheel-arch extensions indicate a stubbier, wider footprint than any current E-Class.

Factoring in reports from our spy photographers of a very vocal exhaust note helps flesh out a picture of an aggressively-sporty beast lurking within.

Indeed, the test mule could be mute confirmation of the next-gen SL’s roots: AMG boss Tobias Moers said in a recent interview with British magazine Autocar that it will in fact share its platform with the next AMG GT, complete with front/mid-mounted engine and rear transaxle.

“We are focused on SL for the future,” he said.

“It’s a totally different car – it’s a sports car. The company has been running at full throttle for two years on that program. It’s a shared platform between GT and SL.

"It will have a perfect compromise between driving dynamics and comfort because it's still kind of a cruiser too," Moers said.

Although there are rumours that the next SL will be a 2+2, it’s clear that it won’t build off the platform used by the current four-door AMG GT, which is shared with the current E-Class/CLS-Class Benz models and incorporates a more conventional driveline in which the gearbox is mated directly to the engine at the front of the car.

Although it once topped the Mercedes-Benz luxury sports car range, the SL has been transcended in recent years by the more focussed GT and the thinking goes that a re-imagined SL would become a more clearly-differentiated link between the thundering GT and the expansively luxurious S-Class Coupe/Cabriolet.

The idea appears to be that Mercedes-Benz would dearly love to grow SL sales in a market that, in Australia at least, clearly favours the GT and the two-door S-Class over the current version.

It’s also being said Mercedes-Benz is considering making the next-gen SL, like the GT, an exclusively AMG product.

Word is that hybrid powertrains – and AWD – will be universal across all AMG models and, in the SL, will include a 3.0-litre inline SL 53 six-cylinder producing around 325kW, a 390kW 4.0-litre SL 53 biturbo V8, an SL 63 with a more powerful 455kW version of the same engine and an SL 73, also based on the 4.0-litre V8 but boosted by a 152kW electric motor to offer close to 600kW.

Anticipated introductory dates vary, but it’s unlikely the new Mercedes-Benz SL will appear before 2022.