May I offer the solution to this "puzzle". There is no such thing as a CLK430 AMG. The owner of that CLK430 Cabriolet thought he could impress others by purchasing the $10 "AMG" badge and sticking it on his car, trying to elevate the status of his own car. I guess driving a $60,000+ convertible wasn't enough for him, he wanted to elevate his status even more. Your local Mercedes dealership can do this for you or you can pickup an "AMG" badge from any tuning shop. I have seen many people with CLK 430's (coupes and convertibles) that put the AMG badge on the back, but I have also seen an S500 AMG before, as well. I have even seen Mercedes vehicles that are completely tagless except for one "AMG" badge on the back and are obviously not AMG cars (I can tell the differences between an AMG car and a regular Benz without looking at the tag). Like I said, the car is really just a CLK430 or S500 or whatever car you see it on...the person just adds the AMG badge to try to impress other people, attempting to fool others into thinking the owner actually has a real AMG car.
I asked my family's Mercedes salesman as to why people do this, and he just said it, plain and simple, that they "can't afford the real thing" (referring to a true AMG car), so they just buy the badge to try to look cool. Pretty damn lame if you ask me...anybody who does that is just a pathetic fool in my book.