Mercedes-Benz is bringing back the gullwing doors that helped make the 1950s-era 300SL coupe one of the most sought-after collector cars. The doors will be among the distinguishing traits of the all-new Mercedes-Benz SLS AMG (www.mbusa.com), which the company will unveil in September at the Frankfurt Motor Show. Like its ancestor, the SLS AMG will have another notable feature: power. Designed and developed by AMG, Mercedes’ high-performance division, the car will have a 6.3-liter V-8 engine that produces 563 hp and 480 ft lbs of torque—sans turbochargers or a supercharger. All that muscle will help the SLS reach 60 mph in 3.7 seconds and a top speed of 196 mph.