I have a 2005 SL500 AMG. I am thinking of selling it, and am trying to appraise it using Edmunds, or kelly blue book. None of them list an SL500 AMG, they all list SL55 AMG. My owners manual and all my documents say SL500. Is this just rare combination? If so does anyone know about how much the AMG package would add to the value of the car, it has 42k miles. THere is only one Mercedes dealer where I live so taking it several places to have it appraised, at least by a Mercedes dealer, is not an option. Thanks.