I've got my eye on a 2001 X5 3.0. It's got about 125k, and is clean inside and out... all the usual places you'd expect to be dirty if there were oil leaks/weeps are clean and shining like new. It looks like the expansion tank is new, as are the tires, brakes, and at least a few of the hoses. Exhaust looks to be free of rust, underside overall looks clean.

I took it for a long test drive, gunned it, stomped the brakes, cornered hard, and found that the ride was really smooth, handling and power were great, with no kinks in shifting or downshifting, and no strange noises, knocks, etc.

I'm a BMW noob, but I'm guessing that by 125k the common high mileage issues have probably occurred already (and hopefully dealt with, if the cleanness of the engine, underside, and test drive performance are any indicators).

The next time I go look at it, I'm planning to eyeball the following things:

1. CV boots (forgot to look there)
2. Suspension (ride was smooth, cornered beautifully, but might as well look.
3. Check the trans for signs of leaks jic. (shifted smoothly during drive)
3. Battery (didn't bring my sockets)
4. Service record (dealer said he has it)

Any suggestions on what else to look for? Ideas greatly appreciated.