Magna said its Magna Steyr unit based in Austria’s Graz — where the rugged Mercedes-Benz G-class SUV is built — would develop and build the aluminum bodies for the upcoming Mercedes-Benz SLS AMG.

“We can be proud that we are the only supplier in Europe able to manufacture a body made only out of aluminum — that underlines once more our leading position in challenging and innovative technologies,” Magna co-CEO Siegfried Wolf said in a statement.

Aluminum is about a third lighter than steel while offering extreme rigidity, but it is also a more complicated material to use in cars than steel due to varying metallic properties. This requires different production methods for tooling, stamping, welding and painting.

The hotly anticipated supercar that hits markets early next year is fitted with two so-called “gullwing” doors that swing upwards for entry. This hallmark design became legendary in the 1950s when Mercedes launched the SL300 sports coupe, which is considered by many to be one of the most beautiful cars ever built.

Ever since the board of General Motors Co. approved a sale of a 55 percent stake in its European unit to a consortium led by Magna last month, rival carmakers such as Volkswagen AG and BMW AG have threatened to withdraw business from the supplier, since the Opel deal would make it a direct competitor.

Daimler CEO Dieter Zetsche told reporters during the Frankfurt auto show last month that he was not concerned, however.

“Magna has stated and confirmed again and again that they would have two totally separate organizations with Chinese walls. When you go to a bank, you have to rely on those Chinese walls as well.

“So if that is a smart step that Magna is taking is one question; does it prevent us from continuing our good business relationship with Magna, the supplier? Clearly no — so I have no problem from that perspective with their decision.”

The SLS AMG arrives next spring. The hand-built coupe will have gull-wing doors, like the 1954 SL300 coupe. The car will use lightweight materials extensively, including an aluminum space frame. The 563-hp, AMG-engineered 6.3-liter V-8 will be teamed with a seven-speed dual-clutch transmission.