The fix to daily short trips is a drive that is 25 or more miles every week or so.

Based on the work you have already done, I think you can handle the CCV job. I don't see anything different that you should be concerned about in the clogged pipe. I am assuming there are no metal shavings since I can think of no reason they would get there.

Certainly your time is worth some amount of $$$ but at probably $100+ an hour you will save if a BMW pro does the work, assuming you will gain confidence in doing other maintenance, will feel some satisfaction and that you can can get answers to any questions along the way, I don't see a downside of DIY unless you can't get at it right away.

The condition of the CCV system is not a certainty that your X has been poorly maintained. Even if that is the case that does not mean it is a certainty to be a maintanence hog. I don't share the experience of those in the maintenance hog camp but I log in the reasons they feel that way and keep a closer watch on what they have had problems with.

I think the optimum purchase of a used X5 is one that has less than 50-60,000 miles on the clock, comes with full maintenance records, 1-2 owner and you can purchase a warranty to cover the expensive stuff--- if there is one out there. That doesn't mean you have made a poor decision if that is not the case for you or that process will be beneficial but it is hard to argue that it won't.

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X5 4.6 2002 Black Sap, Black interior. 2013 X5M Melbourne Red, Bamboo interior
Dallas