The SL class is Mercedes-Benz’s longest-running nameplate, dating back to 1954. It started with the racing-inspired 300 SL, which appeared like a portent from some wondrous future. A convertible version was unveiled simultaneously at the New York Auto Show, and the model has followed the same basic recipe ever since: a sports car hosting the marque’s most powerful engines, leading-edge technology, and luxury materials, built stolidly for cruising the world’s most exclusive postal codes. As a supplement to this venerable formula, Mercedes engineers and designers have created special versions of every iteration of SL, slathering them with alluring dosages of more, adding power and/or enhanced fitments, to create special, typically limited-edition, variants. Here’s a look at the greatest SLs from each of the model’s seven generations. First Generation (W198), 1954 through 1963: The 300 SL Alloy Coupe With its soaring gullwing doors, direct-injected inline-six racing engine, and slippery teardrop shape, the initial..