Edward 
2006 BMW X5 SUV 4.4i 4dr SUV AWD (4.4L 8cyl 6A)
Second X5 and might buy a third one!  
 Without a question, this is the 4WD to have. Pricey vehicle; but the best by all means.  I would have given a perfect reliability score, but a faulty passenger seat sensor that activates the air bag left me without my X5 for 29 DAYS because the spare part had to be ordered from Germany, and part number was not availble???  That said, the dealer loaned me a fantastic 530 for the whole time the X5 was in service and every day they kept me informed about the situation, with a very professional and courteous approach.    