Bought my 06 X5 3.0 off lease in January for $25,500.
CPO 2006 X5 3.0i
I think the used market has firmed up since January and my dealer didn't have the car in inventory, so I think your price is pretty good. Don't worry about the last $1,000. If the truck is in great shape and has a clean CarFax buy it and enjoy.