I think it really depends on your capabilities and interest in doing work on maint and repair yourself. From your post it sounds to me like CPO would be a good choice for you. For me it is a nice to have but not a requirement. I can do almost any repair job myself and I have other vehicles to drive if the X5 is down for awhile. So buying a newer one with CPO is not worth it to me and I seriously doubt if the repairs on mine would be nearly as much as the depreciation and CPO costs on a newer model. But everyone has a different answer to that question, so there is no right or wrong answer.

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2003 4.6is - SOLD
2003 M5 Imola
2008 Mini Cooper S
2011 Mazda CX9