BMWs hold their values well. $22k for a 2003 is a bit too low esp with only 45k miles. If you want a '03 you'd be lookin at least $26k for somethin in good condition. And trust me, you want an X5 in good condition, not trashed. CPO will cost more. Use the CPO search mentioned above.

There is a 6-speed manual X5 CPO at my dealership but I think it's well outta your price range you're lookin for.