Chicago-based tuning firm Speedriven has just released a special tuning package for the Mercedes-Benz SL 600. The amazing thing about this roadster is that it will run on natural gas. This 2007 SL600 Mercedes-Benz is powered by a powerful 5.5-liter twin-turbo V12 that's capable of delivering some 799-horsepower and 1000 lb-ft of peak torque. With all that power it's no wonder that the SL can do 1/4 mile in just 10 seconds.
However, this isn't the world record for the fastest CNG-powered car. That title continues to be held by the Hohenester Audi A4 tuned to 700-horsepower, which allowed it to hit 226 mph in 2009. Speedriven had a goal of hitting 240 mph with their CNG-roadster. Still, not too bad for a "green" Mercedes.