I drive maybe a couple of thousand miles a year. On my 10 335i, in town
seldom on road. Had it a little over 3 years no problem. The 13 X5d
has about the same and hasn't been back to the dealer. Have a vette
that maybe does 200-500 a year no issues. Probably just the fact
she will drive it a little everyday is good.

As much as I hate the maintenance and reliability of both our X's , go with the 4.8 ... My wife's 3.0si is a great ride and I'm sure you'd be happy with it but there is just something special about driving my 4.8 (E53 though). Go out and test drive both you'll see the difference immediately.

If you get the 3.0 , don't test drive a 4.8 afterwards or you'll regret it :rofl:

Got it.

My understanding is that unless you drive the hell out of these cars they will develop clogs and other issues.
Certainly stay on top of the maintenance, and good luck to you with what ever purchase you choose.