You should never trade in or sale a car to a dealer
You'll never make a fair deal. Sell it on the autotrader, ebay, or your local newspaper. you'll get much more. When I bought my X i was going to trade my Z4, the dealer offered me U.S. $23000, I said no, he called 2 days later and offered $24500, refused...The next day he offered $26000... I sold it to a private party for $30k a week later.