Newbie with question about buying an X5.

[axg1040]

I am in the process of looking to buy a 2004,05 or 06 X5 3.0.
I have seen some great deals at CarMax.
Has anybody dealt with them in regards to buying an X5?
I have checked out some CPOs at some dealers here and they appear to be no better than some I have checked out at CarMax. The CPOs are 7-9k more in price (of course with that you get the CPO inspection and warranty).
I checked with the local BMW dealer here and I can buy an extended warranty for $2500 that covers it for another 6 years should I not buy a CPO.
Thanks for the input.
I had my mind set on a Touareg until I began doing some research on the X5 and found this site.