If you want a tricked out MB, you need to get the latest S class...
The SLK has always been one of the simplest MB's around. BUT, it is still a lot more complex then the simplest cars from other manufacturers.
I find it's not really fair to compare a roadster that has the goal of being a light, enjoyable car, to a fully tricked out Lexus.
Yes, a Miata may also have the vario roof, but meanwhile you get Miata owners rejoicing that they're finally getting heated seats, and the SLK had this, plus airscarf from day one. We also have automatic wipers, automatic lights, parktronic, automatic varying airconditioning, DVD playback and many other things, not to mentioned all the cool little info you can get by going to the menus and looking at data such as how many liters of oil is left, the voltage of your battery, the version of the software installed, the number of miles travelled and how long you've spent in the car, etc... (although stupidly, some of this stuff doesn't exist in the US cars).
I belong to a car club and we very often swap vehicles between each other, and let me tell you, some of these people are pretty amazed at all the stuff that's in my car. Of course, some of these people use a Lotus Exige as a daily driver (or some other speedy vehicle), and I have ten fold the gadgets they do.
In fact, few are the people in our club that have "more" in a high end sports car or convertible, and I'm talking about cars like Ferrari 360/360CS/550, Lamborghini Gallardo/Murcielago, a ton of Porches (mostly older, lighter and very stripped out track monsters), Lotus Elise/Exige's, Maserati, Wiesmann and the list goes on. My SLK55 AMG can tango with most of these cars, yet 99% of them don't have jack sh1t compared to the SLK.
The latest vehicle that came around that actually beat what was on offer in my SLK, was probably one owners new GL-class SUV. Yup, from Mercedes...