The temp of my SL320 generally stays in the range of 95-100. I thought there was something wrong but after talking with many people on the forum and other SL owners, I think it is just the design of the vehicle. If you are still concern with the temp, you should ask the dealer to put a new thermostat in for you before you take delivery of the car.
As far as the SL500 is concerned, Marek said it. The 600 is an awesome car and there is not a lot of them around. It is definitely a car to show-off in.

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