Have you been reading Consumer Reports lately?
Merc got trashed. I believe they were the car make with most models to have so many cars make Consumer Report worst list. All of their convertibles, the SUV(shocker), CLK and even the new CLS. Probably Merc's worst showing in a decade.
An AMG like a RUF Porsche, is EXTREMELY expensive to insure. Although the two aren't really the same because AMG is wholly owned by Merc but that makes no difference to the underwriter, they'll stick you with a nice BIG surcharge.
By the way I have no idea how someone can drive Porsche brakes and give that up for what they put on Mercs. Braking is the most underated aspect of a car and I personally could never live with anything I have seen from Merc.
p.s.
I also feel ridiculous driving a four door sedan, like I should be wearing a chauffer's cap on my head.