I also thought the trade-in price Tesla offered me was pretty reasonable though my car's not worth much anyway. I am stressing though about whether Tesla is going to make a fuss about its condition when I turn up on delivery day. My car is almost 10 years old & although it's generally in great condition with very low mileage & good service history, it's got 10 years of accumulated scuffs & scrapes on it! The scrapes don't bother me (most of them were already there when I bought the car) but I really don't want to have my M3 delivery experience messed up by an argument with Tesla about what consititutes normal wear & tear.
From previous comments, it sounds like everything should be fine, but would be interested to hear if anyone has had any issues & how their trade-in the process was conducted.