I was wondering what the value of Matt Holidays 2008 750 LI BMW that I purchased would be. Since I purchased it, I have gotten him to sign the back of both headrest of the front leather seats. I have a copy of the title with he and his wifes name on it and pictures of him in my car signing the headrest. I dont know where to go to find out the value of something such as this. It has just a little over 20k miles on it.