Moving up to an X5...deal or no deal?

[BMWenvy]

I am new to this forum but am not new to the forum world. This looks like a good place to hang out and learn some information.

I'm looking for some opinions from some X5 owners. I'm selling my wife's '07 328i and purchasing a newer X5.

THE X5: I have my eye on a used 2010 X5 35d, 2,800 miles, sport, premium, technology, etc. I don't have the sheet in front of me but I believe it had everything except for the rear dvd player and adaptive cruise. Can't be certified since it is in the current model year (according to the dealer). Priced at $51,988.

THE DEAL: They offered us $32,800 plus on our trade ('07 328i, premium, heated seats, xenon). They just reduced the X5 so only came down about $600 and gave us roughly $19,000 for the trade. I offered $29,500 difference and I would buy it but they aren't budging so far.

It looks like I could sell our car for around $21-22k privately around here. I usually never trade but my wife loves this X5 so might see if I can work the deal any closer to $30k difference and just trade it.

Thoughts on the offer? Good deal or walk away?