Light Front, Runs and Drives, Passenger Airbags Good., , If any top-end motorcar is actually worth a six-figure price, the Mercedes-Benz SL600 might be one of them. The SL600 and the lower-cost SL500 are similar, but the SL600 holds a V-12 engine. Both two-seaters have a retractable hardtop. Mercedes-Benz also offers a high-performance SL55 AMG edition that’s equipped with a more potent V-8, and the SL500 has a new seven-speed-automatic transmission.