SLS Black Series will feature about 600 bhp and 677 Nm of torque. It will be a very limited series, with each unit costing about €260,000. The SLS AMG Black Series is set to debut in 2013.

Reports have emerged that Mercedes-Benz's performance division, AMG, is working on an SLS Black Series set to debut in 2013.

News of the super exclusive Gullwing hypercar has been kicking around for some time now, and finally some details are emerging from Mercedes sources who've spoken to Autocar about what an SLS Black Series will look like.

First off, there has got to be a performance upgrade. The SLS's standard M159 engine, a 6.2 liter V8 power plant with 563 bhp and 648 Nm (479 lb-ft) of torque, will be dialed up to around 600 bhp and 677 Nm (500 lb-ft) of cranking kraft. The Black Series' 0 to 100km/h sprint is expected to fall below 3.5 seconds, from the standard SLS's 3.8. Top speed will rise to from 314 km/h (195 mph) to 335 km/h (208 mph).

AMG will achieve that power upgrade by increasing the compression ratio of the engine, creating a new profile for the camshafts and using a larger air intake manifold. But how much power can AMG continue to squeeze out of that 6.2 liter V8? Plenty.

"We're not at the limit with what's out there the moment. We're saving the best until last," says Friedrich Eichler, head of engine development at AMG.

The SLS Black Series will be a very limited one. It is expected to come with a hefty price tag of about €260,000 (£230,000).