I recently acquired a Mercedes-Benz E500 from a gentlemen who decided it was time to upgrade, when looking over the car I noticed there was a redish s in a circle on the two front doors. He mentioned that it was a marking for some special feature he opted for when he purchased the vehicle I have been looking for quite some while as to what the S means but all I could find is information about the S class mercedes but nothin about an S on an E500. Any links and information would be appreciated