Max, The SL is a great car. I think I have had that car for a couple years now, and have had really no big problems with it since purchased. It now has 136k miles on it. The only down side is normal maintenance parts availability. I have a 96 R129 chassis SL, and I have to order air filters - both engine and cabin. I was down on hydraulic fluid, and had to drive 50 miles round trip to the Mercedes dealer to pick up a litre of fluid for $23 bucks.
I do not regret buying the car one bit. It has ample trunk space, silky smooth ride, handles extremely well, and stops on a dime. The R230 chassis SL you are considering has one thing I wish mine had - a retractable hard top... Mine has both a soft and a hard top. I have the same R230 wheels on my SL, as are on the car in your cl link, and they look real nice.
They are very well built, and do not have the typical body flex that most convertibles have, and since the R230 is a hard top, wind noise should not be an issue.
Here is a link to the best forum I have found for the SL. Some very interesting conversations and info there, from people all over the world.
http://www.benzworld.org/forums/mercedes-benz-roadster-forums/