I traded in my 2003 Audi TT for a SLK 55AMG with all possible options, which I chose to buy over a 2006 SLK 350. This car is incredibly fast. The roar of the engine is music to enthusiasts' ears. The cockpit although somewhat "enclosing", is comfortable, well designed, built with nice materials, and complements the sport look of the exterior. The audio system is a blast. The air scarf, although unpractical for Florida, is very different amenity to have in your car. The exterior attracts lots of attention on the road and while parked. I prefer the top up. Acceleration is a thrill, and gas mileage is not that bad for 8 cylinders.
Acceleration. Style/looks. Audio system. Navigation system. Sport AMG seats. Dashboard
Either eliminate or relocate cup holders. More intuitive navigation system. Lock for gas cap. More visible alarm lights (e.g., such as Audi's). Bigger asthray. Add storage space in the cockpit (e.g., puches, pop-open hiden storage space) to make up for the usless glove compartment.