 I bought my very clean and well maintained X5 used about 2 years ago for about $7K.  After a few thousand spent on the regular stuff, the timing chain guides disintegrated.  After one year in the shop and a $7K repair bill it is still running rough and un-driveable.  It has 118K on it and has been well kept.  My first biggest mistake was buying it and my second biggest was paying to fix it thinking I would have a re-built ride.  Don't be seduced by the comfort and fit/trim/etc.  These things are a ticking time-bomb.  I sort-of enjoyed it for 11 months after buying it even though it was a bit fussy with little stuff during that time.  Basically that breaks down to $1300 per month that I spent on that disaster of an experience.  Also, don't be fooled by the appearance of more than one star as a summary of this review because I had to give credit for comfort, etc.  None of that is good enough to overcome the massive expense of timing chain failure.