I do hope they improve their quality problem. I had so many problems with my '01 C class.

Power windows refused to work, computer error msgs, rear lights went kapoot, weird gas tank errors, stereo went on the fritz and works when you tap it, side mirrors refused to open/close, batteries died and these are the problems I remember. To top it all off they have bad customer service. So bad that they had to pirate the customer care representative from BMW.
I was even forced to email Mercedes Benz in Germany to try to get a proper response and treatment from the local reps here. I still ended up paying for the repairs cause it was "out of warranty". Rather convenient when there isnt enough people with Cs to complain.
I like the SL55 and all but I wouldnt want to buy a potential "problem". I hope the E90 they bring in is a diesel. That would be so sweet.