What makes an already overblown factory-tuned Mercedes even more special? More stuff. Such is the new SLK 55 AMG special series, which gets a horsepower boost via a worked-over version of AMG's 5.5-liter V8. The special edition of the only V8-powered roadster in its segment, gets a 45hp bump from 355 to 400, with an increase in torque from 376 ft.-lbs. to 383 (largely by way of a more substantial engine oil cooler and enhanced airflow). It's also been made lighter with typical placement of carbon fiber — in this case a hardtop made from carbon-fiber-reinforced-plastic (CRP) — giving it a curb weight of 3,296 lbs, or 100 lbs lighter than the base model, and a corresponding improvement in power-to-weight ratio. Even more stuff?: 19-inch AMG forged wheels, AMG height-adjustable torsion sports suspension and AMG high-performance composite brake system (same 7-TRONIC tranny as the base model) and special racing seats. Specs?: naught to 62 mph in 4.5 seconds. All for the equivalent of around $135,900. Sure it's a bargain, in the sense of an all-you-can-eat buffet at Wolfgang Puck's.