I'm upgrading to a P100D and currently have a $55k trade in offer from Tesla for my old car: Blue 2013 P85 w/ carbon fiber décor + spoiler; glass roof; black performance interior; tech package; rear seats; active suspension; paint armor and twin chargers and only 16,900 miles. At the time I think it was almost every upgrade except the stock wheels + upgraded audio. KBB and other sites have the trade in value anywhere from ~62k to ~69k. But I've seen certified pre owned selling for in that range (especially Tesla) to not much higher so that seems a bit high. Going with Tesla also gets me the trade in sales tax credit which be worth around ~$5500.