I currently have an '07 3.2 with 69000 that I've had since Jan I'm the 2nd owner. It has bose and the cold weather and wood. I found an '06 3.2 s-line with cold weather,sensors,navigation with 73300 miles at my mothers BMW dealership for 17800. They said my car with her working and trade in would be 1500-2500 with trade. My Dad wants to get as close as possible to an even trade. How should I work down the price and trade-in value? Is it a good trade off even thoughts it's no Bose and a year older?