I have a 2006 X5 3.0 that is going off lease in another two months. MRSP was around $50K and residual is $29K. The lease included 45K miles, and I will be just about there by the time the lease is up. The dealer is offering to sell it to me for around $26K, or $28K if I want it CPO. How do I know what a good deal would be?

I would love to buy it, because I know where its been, how its been driven, and its in immaculate condition.